







Un bénéfice de 5% 
20080311 

mahiques pose la question : Un propriétaire decide de vendre deux parcelles de terrains pour un montant total de 141750 F. Il fait un bénéfice de 15% sur la première et une perte de 10% sur la deuxième. L'ensemble de la transaction lui a rapporté un bénéfice de 5%.combien atil vendu chacune des parcelles ? PierreLouis Gagnon lui répond. 





exercices corrigés 
20070109 

Zribi pose la question : si je peut avoir des exercice corrigé Claude Tardif lui répond. 





Matrice 
20060201 

Kader pose la question : mon probleme est le suivant soit deux matrices carrees A et B d'ordre n qui sont anticommutatives AB= BA , demontrer que au moins une des deux matrices n'est pas inversible si n est impair.
je n'arrive pas a utiliser le fait que n soit impair, trouver le rapport entre n impair et inverse des matrices, je pars sur la base de DETAB=DETA*DETB Claude Tardif lui répond. 





probleme de matrice 
20060201 

Un eleve pose la question : mon probleme est le suivant soit deux matrices carrees A et B d'ordre n qui sont anticommutatives AB= BA , demontrer que au moins une des deux matrices n'est pas inversible si n est impair. Claude Tardif lui répond. 





La bissectrice de l'angle ABC 
20000216 

Laurent Gauthier pose la question : Estce redondant d'ecrire "angle ABC" avec un accent circonflexe sur le B? Peuton ou devraiton se contenter d'ecrire soit ABC (avec l'accent), soit l'angle ABC (sans accent) ? Le contexte dans lequel ceci apparait est le syntagme "la bissectrice de l'angle ABC", c'estadire que je me demande si on devrait ecrire "la bissectrice ABC " (avec accent), "la bissectrice de l'angle ABC" (sans accent) ou "la bissectrice de l'angle ABC" (avec accent). Claude Tardif lui répond. 





30 % off 
20210907 

Corrine pose la question : When I am shopping for clothing that is for sale, the advertisement may say the item is 30% off. The original price was $70. How much would it now be? (how do I figure that out?) Thank you! Penny Nom lui répond. 





Adding a service charge and the VAT 
20200430 

richard pose la question : was given a figure by a client been performance bonus of staff , the figure is 806,698.35 from this 806,698.35 is my company service charge of 10% and 5% of the service charge will be Vat to government in summary from 806,698.35 is 10% of service charge and 5% of service charge is the VAT Penny Nom lui répond. 





What was the original price? 
20200201 

Gracie pose la question : If you buy something for $6.30 and it’s 30%off what was the original price? Penny Nom lui répond. 





Roll two dice and record the difference 
20191209 

Barbara pose la question : Suppose you roll two dice 100 times. Each time you record their difference
(always subtracting the smaller one from the bigger one to get a positive
difference). The possible values you get are 0,1,2,3,4 and 5. You record
the frequency of each value in the following table:
Difference of two dice 0 1 2 3 4 5
Observed frequency 12 31 26 13 10 8
Let your null hypothesis be that the dice are fair, and the alternative
hypothesis be that they are not fair. Using a confidence level of α = 0.10,
test the null hypothesis by a goodnessoffit test.
Hint: begin by
completing table:
x 0 1 2 3 4 5
f(x) Penny Nom lui répond. 





What is the original price? 
20190515 

Tyler pose la question : if 45% of an item is $90.00, then what is the original price Penny Nom lui répond. 





80% of an item is $200.00 80% of an item is $200.00 
20190425 

kayla pose la question : if 80% of a item is $200.00 what is the original price Penny Nom lui répond. 





A dice game 
20190317 

Remo pose la question : So, little game my kid came up with.
Dice are standard d6.
I roll a die, he rolls a die. If he gets the same number as me OR a bigger number he wins.
So far so good. Used the opportunity to get him to calculate the probabilities of him winning, see if I could get him interested into looking at this game from a more academic perspective. He did fine.
Then we upped the ante.
He rolls one die, I roll two dice. I his die has a number that is equal or greater than both of mine, he wins.
We had a bit of trouble solving that one, and had to resort to a table with all the results ( 6x36) to figure out where we stood.
Then again we upped.
He rolls two dice, I roll two dice.
If any one of his dice has a number equal to or greater than both of mine he wins. I only win if one of my dice is greater than both of his.
And we got stuck. Figured I would need to find a formula to resolve this one, as our earlier solution ( table everything ) suddenly is 36x36, giving well over a thousand possible results. And if we ever go bigger than that then we *really* are going to need another way to calculate it. Harley Weston lui répond. 





Margin with commission as part of selling price 
20190213 

Anni pose la question : I need to find selling price to put us at 24% margin.
15% commission is based on selling price and is included in our cost.
I'm trying to do it excel and keep getting a circular reference.
Total cost= cost + commission (15% of selling price)
Selling price=total cost + 24% margin Penny Nom lui répond. 





An ice cream cone 
20190205 

Eyuel pose la question : a scoop of ice cream has a 3inch radius how tall should the ice cream cone at the same radius be in order to contain all of the ice creams inside the cone Penny Nom lui répond. 





Sale price and employee discount 
20190118 

Margaret pose la question : What is the formula to find the
75% off full price item that was already marked 30% off? Penny Nom lui répond. 





Price before VAT and a discount 
20181115 

Carol pose la question : I bought a computer for £330.
The selling price included VAT at 20%.
Then I was allowed a staff discount of £30.
What was it’s original price before the VAT and staff discount? Penny Nom lui répond. 





The price of eggs rises 10 cents per dozen 
20181110 

Maddie pose la question : Hi! I'm currently struggling with a word problem that says:
"If the price of eggs rises 10 cents per dozen, one will be able to get 2 dozen fewer eggs with $6.00 than was possible at the lower price. What is the lower price?
We are working on completing the square and all of the problems I've done so far in this chapter require using that method. If possible and needed, could you explain how to set up the equation?
Thank you so much! I appreciate all your help!! Penny Nom lui répond. 





Rolling 2 dice 
20180406 

Jose pose la question : Find the probability p that the sum is as stated when a pair of dice is rolled.
(a) Even and doubles.
p=
(b) Even or doubles.
p= Penny Nom lui répond. 





The price of a sheet of metal 
20180402 

Nydia pose la question : What is the formula to calculate the following:
I nee to find out what the sheet price be. The dimensions are 2000x3000 mm into ft they are 78x1181.
The sqft price I have is $22.16. How do I figure out the sheet price from that? Penny Nom lui répond. 





An item on sale costs 55% of the original price. 
20180228 

Debra pose la question : An item on sale costs
55%
of the original price. The original price was
$51
. Penny Nom lui répond. 





The wholesale price given the retail price and the markup 
20180207 

Matthew pose la question : Retail $99
Markup is 80%
What is the equation to find the original (wholesale) price (55)?
thanks Penny Nom lui répond. 





Average price 
20170915 

Annette pose la question : If I sold a widget at $15.50 17.5% of the time and $16.50 88.5% of the time what is the algebraic expression for that. How do I arrive at an average price Penny Nom lui répond. 





What is the regular price? 
20170511 

Saira pose la question : If the sale price is 55.50$ and the discount is 12% what is the regular price Penny Nom lui répond. 





Selling price and markup 
20170424 

Julie pose la question : What would the cost of an item be, if the sell price was $50 and the markup 48% Penny Nom lui répond. 





How do I establish the original List Price? 
20170115 

Bob pose la question : (1) I have a net price item at $4,664.66 but do not have the discount percentage. I have been told I received 40%? How do I establish the original List Price and to confirm what discount I received? Penny Nom lui répond. 





Selina saved $6 on a 20% off sale 
20161014 

Myra pose la question : I don't know how to help my child answer this question  Selina bought a shirt on sale that was 20% less than the original price. The original price was $6 more than the sale price. What was the original price? Penny Nom lui répond. 





A 15% discount 
20160809 

eunice pose la question : brian brought a printer sale at the store. the discount was 15%, and brian saved 550. what was the printer original price? Penny Nom lui répond. 





A 70% off sale 
20160511 

virginia pose la question : If the sale price is $129.99 @ 70% off  what was the original price? Penny Nom lui répond. 





The original price before a discount and taxes 
20151209 

Michelle pose la question : Good day,
I would like to know if there is a particular equation to validate the following information:
I had to find the original cost of an item sold for 759.36$ before a 25% discount and 13% taxes.
I know we must use separate question to obtain the answer but I am unsure how to write the equation to validate my answer. Penny Nom lui répond. 





Two price reductions and a coupon 
20150916 

Suszanne pose la question : Mary purchased an item for 45% off the original price, plus an additional 20% off the sale price.She also had a $5 off coupon, which the salesclerk applied after these two discounts. Mary's final purchase price for the item was $50. She paid no sales tax, what was the original price of the item? Penny Nom lui répond. 





Order of operations 
20150912 

Tanisha pose la question : I would just like to double check if something like 5x squared times 4x cubed equals 20x to the power of 5??
It's just that we were told you can only answer an equation like this if the base is the same...so does that mean the x part or the whole thing like 5x?
I'm sorry if that didn't make sense!
Thank you for your help!! Penny Nom lui répond. 





A cone of maximum volume 
20150316 

Mary pose la question : I have to use a 8 1/2 inch by 11 inch piece of paper to make a cone that will hold the maximum amount of ice cream possible by only filling it to the top of the cone. I am then supposed to write a function for the volume of my cone and use my graphing calculator to determine the radius and height of the circle. I am so confused, and other than being able to cut the paper into the circle, I do not know where to start. Thank you for your help! Mary Robert Dawson lui répond. 





What is our cost? 
20150127 

Johanna pose la question : I have a pieces of 3/4" sch40 (round tube) 240" long at $70. What is our cost. We also add 35% to our cost for selling price. How do I figure this out? Penny Nom lui répond. 





Selling items at a reduced price 
20150109 

Kent pose la question : I have an item I sell for $19.95 and make a profit of $10.97 for each sale.
If I reduce the price to $14.97, my profit is $5.99 each sale.
Is there a formula to determine how many more I would need to sell
at $5.99 per sale to make the same net cash (profit) as selling at $10.97 per sale? Penny Nom lui répond. 





A price increase and a consumption decrease 
20140816 

sujan pose la question : If the price of petrol increases by 25% and Rajesh intends to spend only 15% more on petrol then by how much % should he reduce the quantity of petrol he buys? Penny Nom lui répond. 





Speed, distance, time 
20140813 

Aarti pose la question : a theif running at 8 km/hr is chased by a policeman whose speed is 10km/hr.if the thief is 100 m ahead the policeman then what will b time required for the policeman to catch the thief? Tyler Wood lui répond. 





What was the selling price? 
20140425 

Con pose la question : Apple built 40 32GB wifi iPads, gave away two in a contest, and sold the rest at two times the manufacturing price. If the company's total profit was $10,782, what is the selling price of one of these iPads? Penny Nom lui répond. 





A conditional probability problem 
20140413 

Chiluya pose la question : Two fair dice are rolled. what is the probability that the number on the first die was at least as large as 4 given that the sum of the two dice was 8? Penny Nom lui répond. 





Graphing piecewise functions 
20140329 

Rayven pose la question : Hi! I'm in eighth grade, taking ninth grade algebra 1. I'm confused as to how to
graph piecewise functions. I know that you have already answered a question similar to this
(I did my research first) but it didn't completely help me on my homework. I have to graph
piecewise functions for the specified domains, and create a table for the absolute values.
I know that two bars around a number means absolute value (two bars around 2 makes it +2)
, but how do I graph and chart the absolute value for the following:
f(x)= x+3  for 5≤x≤3
And then graph and chart: (on a separate graph):
f(x)= {x if x≤0
{x+1 if x <0
thank you!
~Rayven Penny Nom lui répond. 





Determine the selling price 
20140308 

augustine pose la question : knowing an auctioneer charges a 7% fee and I know I want $74,400 what is the formula to determine selling price. Penny Nom lui répond. 





Finding the retail price 
20140222 

Judy pose la question : An item is currently on sale at 37% off the retail price. The item now sells for $350.
My Question:
What is the retail price and what is the formula or steps to figuring that out? Penny Nom lui répond. 





A sale price for a TV 
20131128 

tom pose la question : a TV can be purchased for $278 normally is $328. what is the percent of the present cost of this TV will you be saving? Penny Nom lui répond. 





Matrices 
20131110 

Ricky pose la question : Why must we have brackets around matrices. Why don't we just neatly write an array of entries crosswise and up and down to indicate a particular matrix? Chris Fisher lui répond. 





Price, revenue and profit 
20130922 

lorraine pose la question : What price maximizes revenue? What price maximizes profit?
The only data I'm given is total output, total revenue, and total cost.
I'm not sure how to set up a formula Penny Nom lui répond. 





Dice 
20130514 

Julia pose la question : What is the probability of rolling(as many times as necessary) a die and getting a total number(sum) when all the rolls are added together of 11? Lorraine Dame lui répond. 





What is the original price? 
20130425 

Dylan pose la question : shirts on sale for 25% off, the sale price is 12.75. What is the original price? Penny Nom lui répond. 





Row echelon form 
20130315 

Shawn pose la question : Please help me put matrix in row echelon form:
1 9 8 0
5 8 1 35
1 4 1 17 Penny Nom lui répond. 





Markup and discount to get a sale price 
20130302 

Warren pose la question :
If you are an ardent shopper you will be aware of the discount (% decrease) marketing strategy to produce the sale price. I began to wonder just how much markup (% increase) was added initially to an item in order to deliver the discounted sale price.
It was simple to construct a formula to convert one to the other.
For example a 30% (mark down) decrease in price required a 42.86% (mark up) to increase the price initially to Tag price. However when I started apply the formulae to a number of circumstances I noticed some very interesting circumstances associated with this relationship
For example a 99.999999% decrease is numerically equal to a 9,999,999,925% increase (huge ratio difference) while conversely a 0.1% decrease is numerically equal to a 0.10010010% increase (Infinitesimally small ratio difference) so the patterns appears logarithmic not linear.
However what really caught my attention was this pattern
See http://www.ozsmart.com/doc/percentage.htm
My questions is why does the decline in the ratio of increases in required mark up (%) price peak at 50 and 51% precisely and then expand again as the percentage move higher
Any explanation would be appreciated Harley Weston lui répond. 





Your profit should be 20% of your cost 
20130221 

anis pose la question : if the customer says your profit should be 20% of your cost..
1) my selling value should be cost +20% of cost = SP
or
2)cost / 0.80 = SP which is correct...if the second answer is right how should i justify my customer Penny Nom lui répond. 





We have 2 teams of 6 couples each that play 6 games 
20130125 

Denise pose la question : We put together a game night where we have 2 teams of 6 couples each that play 6 games. We haven't been able to figure out an arrangement that allows each couple to play each game with a different couple from the opposite team (i.e. Team A couples play every game with a different couple from Team B). Is this possible? It works with 2 teams of 5 couples each. Chris Fisher lui répond. 





The area of a triangle given its vertices 
20121127 

elizabeth pose la question : how to calculate the area of a triangle using points ABC a (2,5) b ( 4,3) c ( 6, 1) Penny Nom lui répond. 





The difference of the numbers on two dice 
20120819 

dilys pose la question : Two fair dice are thrown. Find the probability that the difference of the two numbers is divisible by 4? Chris Fisher and Lorraine Dame lui répond. 





The maximum distance from the vertex of a triangle 
20120502 

David pose la question : There are three towns A,B,and C, equidistant apart.
A car is 3 miles from town A, and 4 miles from town B.
(ie, somehwere outside of the triangle which the three towns form)
What is the maximum distance that the car can be from town A?
This was asked as quiz question in my local pub last Sunday.
The answer is 7. How do I prove it?
Best regards. David in Denton. Robert Dawson and Chris Fisher lui répond. 





What is the better price? 
20120330 

john pose la question : What is the better price?
If a bag of mulch sells for $6.75 and contains 2.7 cubit feet versus a bag selling for $5.99 and contains 2 cubit feet.
Which is the better value? Penny Nom lui répond. 





The price per square inch of a pizza 
20120317 

jordan pose la question : pizzaz pizza sells a small pizza for $10.99.it has a diameter 10 inches.what is th price per square inch ? Penny Nom lui répond. 





Rolling three dice 
20120126 

Aishwarya pose la question : A red, a blue and a green die are all thrown at the same time. Display all the possible outcomes in a suitable way. Find the probability of obtaining:
1. A total of 18 on the three dice
2. a total of 4 on the three dice
3. a total of 10 on the three dice
4. a total of 15 on the three dice
5. a total of 7 on the three dice
6. the same number on each die.. Robert Dawson lui répond. 





A cube of ice is melting 
20111205 

Emily pose la question : a cube of ice (i.e.) each side is of the same length) is melting at a rate such that the length of each side is decreasing at a rate of 5cm per hour. how fast is the volume of the cube decreasing (in cubic cm per hour) at the instant the length of each side is 25cm? Penny Nom lui répond. 





What was the cost price of the article? 
20111110 

tashana pose la question : By selling an article for $320,the profit was 20% of the cost price.what was the cost price of the article. Penny Nom lui répond. 





6 faces and 8 corners 
20110304 

noemi pose la question : jeff made a figure with 6 faces the figure has 8 corners all of the faces are the same size and shape what figure did jeff make Penny Nom lui répond. 





Vertices and sides of a polygon 
20110304 

RINA pose la question : My questions is : would a vertices and sides of a polygon be the same number. For example, a octagon it has 8 points and 8 sides. Am i correct? Robert Dawson lui répond. 





The height of an iceberg 
20101216 

Sharon pose la question : if an iceberg can be seen 10% or 70 meters above the water, what is the measurement in meters of the iceberg below the surface of the water? Robert Dawson and Penny Nom lui répond. 





Geocaching 
20101015 

Clint pose la question : I am stuck on a puzzle for Geocaching which is a GPS game.
I know it is a number matrix but don't know how to start.
[1 7 16 3 9; 1 3 18 20 33] x [1 8 9 3 5; 0 1 0 4 2; 0 0 1 2 1; 0 0 0 1 1; 0 0 0 0 1] = ? Stephen La Rocque lui répond. 





Selling price, cost and profit 
20100622 

Alex pose la question : The profit on a certain television set is 16.5% of the cost price. If the profit is $330,
Find:
a) the cost price
b)the selling price of the television Penny Nom lui répond. 





The vertices of an equilateral triangle 
20100219 

Emma pose la question : If two of the vertices of an equilateral triangle are (2,1) and (6,5), what
are the two possible coordinates of the third side of the triangle? Answer
in radical form. Tyler Wood lui répond. 





The price before tax 
20100215 

dawn pose la question : the sale tax on a cape was 6%,and total price with tax was $92.75,what was the price of the cape? Penny Nom lui répond. 





A triangular pyramid 
20100105 

ally pose la question : how many vertices, edges, faces in a triangular pyramid? Robert Dawson lui répond. 





Find the original price 
20091106 

Cyndy pose la question : Find the original price of a pair of shoes if the sale price is $98.00 after a 30% discount. Penny Nom lui répond. 





Commodity price increase 
20091104 

bharat pose la question : if price of a commodity increases by x% the to keep the expenditure same
the decrease in consumption should be (x/(x+100))*100, why? Penny Nom lui répond. 





A single die is rolled twice 
20091103 

Michelle pose la question : A single die is rolled twice. Find the probability of getting two numbers whose sum exceeds 5.
I can't seem to come up with any of these answers, Help. A. 0.72 B. 0.89 C. 0.68 D. 0.58 Penny Nom lui répond. 





Toss a coin and roll a die 
20090921 

Celeste pose la question : Can you please tell me how to set up this problem to find the answer. I know they are independent from there I don't know.
a coin and a regular sixsided die are tossed together once. What is the probability that the coin shows a head or the die has a 5 on the upward face? Penny Nom lui répond. 





A trillion grains of rice 
20090914 

akaila pose la question : can 1trillion rice grains fit in a classroom with the area of 144.4m3 Penny Nom lui répond. 





Price increases and decreases 
20090902 

craig pose la question : I work for an industry that bases it price increases and decreases on commodity pricing  Customer get confused on how/why we calculated new prices due to movement in the market 
Price go up x% for every $10 of movement in the market 
For this example
Movement went down by $30 and it is 2% for every $10  so price decrease was 6%.
Customer's price is currently $100.
We say  $100/1.06= new price of $94.3
Customer says  $100*.94= new price of $94.
They don't understand that if board went back up $30 which would be 6% increase, they wouldn't be back at $100 if they multiplied on the price decrease.
$94*1.06=$99.64 vs. $94.3*1.06=$100 (Back to the original price)
What is the best way to explain to customer besides using this example?
Any help or info is appreciated.
Craig Victoria West lui répond. 





Percentage price change 
20090827 

alicia pose la question : what is the percentage price change between R66R10 if the answer between the two is R56 Penny Nom lui répond. 





The taxable part of an invoice 
20090825 

Carol pose la question : Question from CAROL:
THE INVOICE TOTAL IS 2731.90 BUT IT DOES NOT SHOW WHAT THE NET AMOUNT IS
THAT THE STATED GST OF 121.90 IS. HOW DO I CALCULATE THE NET AMOUNT THAT
THIS GST AMOUNT REFERS TO? Harley Weston lui répond. 





Torricelli's trumpet 
20090729 

Gary pose la question : I was reading about torricelli's trumpet which is described by the equation1/x which is then rotated around the x axis which results in a figure which looks like a trumpet. Now in order to find the volume the integral 1/x^2 dx is used which diverges when integrated so the volume is finite.However if you integrate 1/x dx which is the formula on the plane the answer diverges. Now if you took an infinite area then rotated it around the x axis shouldn't you get an infinite volume? Notice the area I am talking about is under the line 1/x not the surface area of the trumpet which is what the painters paradox is about What am I missing? Thanks Robert Dawson lui répond. 





The retail price for an ice cream scoop 
20090705 

Patricia pose la question : Hi  I am trying to figure out the fairest retail price for an ice cream scoop. We have an ice cream parlor
and the cost of the ice cream we buy by the bulk container has recently been increased so now we must charge
more for our scoops. We pay a wholesale price of $25.40 for 242 ounces of ice cream. The cost per ounce is
$0.105. What is the formula for figuring out how much to charge retail per scoop? This is probably so simple
but confusing to me. Please help. Thank you! Harley Weston lui répond. 





Unit Price 
20090608 

MATTHEW pose la question : Question from Matt:
I quoted my customer $112.50 per 1,000 sheets per linear yards. My client said I was to high. I need to be at 18 cents per square inch. If I matched his 18 cents per square ines what would my linear yards per 1,000 sheets price be? It comes on a 12.5 inch roll. Janice Cotcher lui répond. 





Two dice and the difference of squares 
20090421 

dave pose la question : I dont understand how to do this: Two fair dice are rolled. What is the probability that the difference of the squares of the numbers is divisible by three? the answer is 5/9 Harley Weston lui répond. 





Choices at a restaurant 
20090413 

Rob pose la question : There is a restaurant you get:
Rice/Noodles (1) 
Main Ingredient (any) 
Sauce (1) 
1 
1 
1 
2 
2 
2 
3 
3 
3 
4 
4 
4 
5 
5 
5 
6 
6 
6 
7 
7 


8 


9 


10 


11 


12 

So the question is how many different combinations are there. You can only have 1 rice/noodles in a selection and only 1 sauce in a selection but you can have between 1 and all twelve mains in a selection. there are 7 rice/noodles , 12 mains and 6 sauces. How many possibilies. I did it mentally in the restuarant, no pen, paper or calculater and i got 3276..i think thats wrong. please help
Rob Robert Dawson, Stephen La Rocque and Claude Tardif lui répond. 





The axiom of choice and constructibe sets 
20090410 

sydney pose la question : The axiom of choice asserts the existence of certain sets, but does not construct the set. What does "construct" mean here? For example, does it require showing the existence and uniqueness of some function yielding the set? In general, what does it mean to require the existence of a mathematical object be tied to a construction of it? Claude Tardif lui répond. 





A large, hollow, ice cream cone 
20090403 

Darah pose la question : A manufacturer is making a large, hollow, ice cream cone to serve as an ad for a local BaskinRobbins. The ice cream cone is made up of a cone with height 8 feet, topped by a hemisphere with radius 6 feet. How much ice cream could the hollow object hold? If a gallon is 0.13368 cubic feet, how many gallons does it hold? If 3 gallons of BaskinRobbins heavy cream chocolate blend weighs 24 pounds, how much would the ice cream cone weigh, excluding the weight of the construction material? Stephen La Rocque lui répond. 





Grain of rice on a chess board 
20090330 

andy pose la question : Is there an easy way for my students to find out 8 to the power of 21 to solve the grains of rice doubling investigation on a chessboard? Any suggestions welcome. Thanks very much Robert Dawson and Claude Tardif lui répond. 





Find the retail price 
20090318 

Allie pose la question : If you have food that costs $0.75 per portion and your food cost is 16.5% how would you find the retail price? Penny Nom lui répond. 





License plates and poker hands 
20090314 

CC pose la question : You have a license plate it can have 6 numbers/letters you can use the numerals 09 and the letters AZ how many combos are possible and how did you figure it out?
Question 2,
Your dealt an Omaha hand You have KKKQQ, how many different hands can consist of the same cards. Harley Weston lui répond. 





15 flavors of ice cream 
20090311 

Pedro pose la question : I was given this word question an was somewhat confused can u help me understand.
An ice cream vendor sells 15 flavors of ice cream and u want to sample at least
4 different types. how many different combinations of ice cream would u be able
to sample? Penny Nom lui répond. 





A shape with 10 sides 
20090303 

Sandra pose la question : One of my son's math questions is as follows:
Suppose I have a shape with 10 sides. I choose a vertex then draw lines to the other vertices that dont share sides with the first vertex. How many vertices will that be and why? Penny Nom lui répond. 





A triangular pyramid 
20090226 

Craig pose la question : Can you help with this question:
Write the names of the faces and the number of each kind of face on a triangular
pyramid? Penny Nom lui répond. 





Vertices, edges and faces 
20090219 

Deb pose la question : I have been reading the responses you have to whether or not a cone and cylinder have edges, and whether a cone has a vertex. I have also found differing answers in different books and websites. Your idea that it depends why we want to call it a vertex or edge is interesting but does not help the students next year when they have a different teacher who tells them that whatever decision I make is wrong! It also doesn't help them when they do the provincial testing. Does anyone know if EQAO considers them vertices or edges? I want to know because textbooks and provincial tests often ask the students to count the number of faces, edges, and vertices or to describe a solid by using these, or to identify a solid that they have described. We need to have consistency in what we are teaching! Chris Fisher lui répond. 





The column space of a matrix 
20090212 

John pose la question : Question from John, a student:
A=
1 1 0 0
1 1 0 0
0 0 1 0
0 0 1 1
B=
1 5 6
1 5 6
0 7 2
0 0 9
Is the space spanned by the columns of A the same as the space spanned by the columns of B? Harley Weston lui répond. 





Faces, edges and vertices 
20090204 

sheila pose la question : what is the relationship between the number of faces and the number of edges of a triangular pyramid ? Penny Nom lui répond. 





Calculating markup 
20090203 

Tonya pose la question : I'm trying to figure out the formula for the following, I have a product that I want to receive a certain profit, but with this product I also have to pay a percentage of commission to someone. I need to know how to calculate my new selling price taking into account the markup percentage, but I don't want my cut to be lowered. I have calculated the markup percentage to get my new selling price with the commission, but it lowers my cut once I pay the commission and I don't want it to do that. Thanks Penny Nom lui répond. 





A die is loaded so that... 
20090130 

Larry pose la question : Hi. I'm having trouble solving this problem. Would you be kind enough to point me in the right direction?
A die is loaded so that the probability of a particular face rolling up is proportional to the number of dots
on the face. In other words, getting a six is three times as probable as getting a two. what is the probability
of getting an even number in one toss? Victoria West lui répond. 





PST and GST 
20090120 

janet pose la question : Hello
I need to figure what one would pay pst 8% gst 5% on a total of $1700.00
I have a small business some pay with cash I need to calculate the taxes in reverse Can you help with formula that the government might like
Thank you
Janet Harley Weston lui répond. 





License plates 
20081117 

Clayton pose la question : Okay, so in this situation a license plate must have four letters (AZ) and four numbers (09), ex. ABCD1234, where repeating a letter or number is allowed ex. AAAA1234, or ABCD1111, or AAAA1111. The order of letters first numbers second, or number first, letters second is allowable, and each state has its own plates, so ABCD1234 from New York, and ABCD1234 from Minnesota are considered different combinations, how many different license plates could there be? Penny Nom lui répond. 





Confusion in a multiple choice question 
20081114 

BJ pose la question : My son got this math problem which he could mostly solve. Here it is:
The highest location in a certain country is 4525 m above sea level. The lowest point in the same country is 192 m below sea level.
a) Find the difference of the two elevations. His answer: a(b)= a+b or 4525(192)= 4525+192=4717 m. No problem.
b) A city is 2221 m above sea level. Is this elevation closer to the highest point or the lowest point?
His answer: highest point because: 45252221= 2304 m (closest to the highest point) and 2221(192)=2221+192= 2413 m. (farthest to the lowest point). OK so far.
But then he was given 4 choices for this question with no other information:
a) 4717 m; lowest b) 4333 m; lowest c) 4333 m; highest d) 4717 m; highest
What does it mean? What's the connection with the rest of the problem? Harley Weston lui répond. 





The volume of a slice from a wedge 
20081016 

Jeff pose la question : If I have a wedge shaped object (ie, a triangle of nonspecific type
extruded along a length) and it is sliced from the twocorner base at
one end to the onepoint tip at the other, what is the volume of the
upper (smaller) part as a percentage of the whole? I hope I have
explained it clearly enough. Thanks. Harley Weston lui répond. 





The vertices of a triangle 
20080927 

T. pose la question : how do you find the coordinates of the vertices of the triangle with the sides determined by the graphs of the following equations:4x+3y+1=0,4x3y17=0,4x9y+13=0? Harley Weston lui répond. 





A multiple choice exam 
20080913 

Phalange pose la question : A multiple choice exam consists of 12 questions, each having 5 possible answers. To pass, you must answer at least 9 out of 12 questions correctly. What is the probability of passing if:
a. You go into the exam without knowing a thing, and have to resort to pure guessing?
b. You have studied enough so that on each question, 3 choices can be eliminated. But then you have to make a pure guess between the remaining 2 choices.
c. You have studied enough so that you know for sure the correct answer on 2 questions. For the remaining 10 questions you have to resort to pure guessing. Harley Weston lui répond. 





A price reduction and a discount 
20080911 

Rita pose la question : A store advertises that during its Labor Day sale $15 will be deducted from every purchase over $100. In addition, after the deduction is taken, the store offers an earlybird discount of 20% to any person who makes a purchase before 10 a.m. If Hakeem makes a purchase of x dollars,
x > 100, at 8 a.m., what, in terms of x, is the cost of Hakeem's purchase?
(1) 0.20x  15 (3) 0.85x  20
(2) 0.20x 3 (4) 0.80x  12 Penny Nom lui répond. 





The selling price 
20080904 

Robert pose la question : Client wants to sell his property providing he is left with 100000.00$ net.
How do I calculate selling price if commission is 6% and taxes on the commission 6% Fed and 7.5%prov.
I'm taking the real estate class and this one really got me. Penny Nom lui répond. 





A linear system 
20080823 

dipesh pose la question : consider the system of equations
x6y+2z=5
2x9yz=14
4x+12y3z=19 by reducing the augm matrix to row echelon form, find
the solution to the equation.
leaving the first two equations the third is changed to 3x+6y+14z=31
show the equations have infinitely many solutions and give a general
formula for them Penny Nom lui répond. 





Joining vertices in a polygon 
20080818 

Megan pose la question : I'm trying to develop a relationship between the number of points of a regular polygon and the
(a) number of lines you could draw between those points,
(b) number of triangles you could draw,
(c) number of quadrilaterals,
etc. Penny Nom lui répond. 





What is the GST component? 
20080611 

Jilly pose la question : I need to find a quick and easy formula for finding the gst (10%) of the total amount in $ terms, eg: the total is $500 what is the gst component? Penny Nom lui répond. 





Calculating a price based on markup 
20080603 

Sheldon pose la question : I know the most common form for retail businesses of calculating a price based on markup is:
Cost/(1  Markup), but how is this supposed to work for a business that desires a markup of over 100%. Harley Weston lui répond. 





Selling price 
20080510 

Roxane pose la question : I'm trying to figure out the formula for the following, I have a product that
I want to receive a certain profit margin, but with this product I also have
to pay a percentage of commission to someone. I need to know how to
calculate my new selling price taking into account the markup percentage, but
I don't want my gross margin to be lowered. I have calculated the markup
percentage to get my new selling price with the commission, but it lowers
my profit margin once I pay the commission and I don't want it to do that. Penny Nom lui répond. 





Determinants 
20080502 

Henry pose la question : I have a question about solving 3x3 matrices.
The traditional way, or at least the way I've been taught, is that if one has a 3x3 matrix such as:
[ a b c ]
[ d e f ]
[ g h i ]
one solves it according to this formula:
[ei  hf)  (bi  hc) + (bf  ec) = determinant.
According to a book I'm now studying to prepare for the California CSET exam, there is another, easier, way to solve it:
[ a b c ] [ a b ]
[ d e f ] [ d e ]
[ g h i ] [ g h ]
In other words, one repeats the first two rows of the matrix and adds them to the right.
At this point, the determinant is calculated thus:
(aei) +(bfg) + (cdh)  (gec)  (hfa)  (idb).
Is this, in fact, correct? Harley Weston lui répond. 





The maximum area of a pizza slice 
20080412 

charles pose la question : A slice of pizza in the form of a sector of a circle has a perimeter of 24 inches. what value for the radius of the pizza makes the slice largest[when o is the central angle in radians, the area of the sector is given by A= r^20/2and the length on the circle is given by s=r0 Harley Weston lui répond. 





Matrix multiplication 
20080408 

manashi pose la question : i. why matrix division is not possible?
ii.when we add or subtract two matrix , getting the result by addind or subtracting correspondind elements....but in case of multiplication it is not but why? Harley Weston lui répond. 





A shape 
20080403 

Joshua pose la question : what shape has 4 faces, 4 corners and 9 edges. Penny Nom lui répond. 





The number of faces and vertices in a pyramid 
20080402 

Laurie pose la question : Can you find a connection between the number of faces and vertices in a pyramid and the number of sides of it's base??? Penny Nom lui répond. 





Some solid figures 
20080228 

tiffany pose la question : What solid figure could have? It has 4 more edges than vertices, Penny Nom lui répond. 





Rolling a 5 before an 11 
20080227 

Jeremy pose la question : If rolling two sixsided dice, what is the probability that a sum of 5 will be rolled before a sum of 11? Stephen La Rocque and Harley Weston lui répond. 





A line drawn between 2 vertices 
20080226 

Arshad pose la question : what is a line drawn between 2 vertices which are not next to each other called. Penny Nom lui répond. 





Actural cost, selling price and commission 
20080221 

LiSa pose la question : I have a question about a few things if anyone can answer...
ex.
actual cost (AC) = $1000
selling price (SP) = $
amount earned for company (C) = 15% of... selling price?
commission 1 (C1) = 2.5%
commission 2 (C2) = 2.5%
How would you calculate how much the company's commission amount would be as well as the amounts for the other 2 that get 2.5%? And what would the selling price be? (the 15% $ + 2.5% $ + 2.5% $ ?)
Is the 2.5% taken from the original amount? I am soooo confused!
If anyone could help, that would be great! Harley Weston lui répond. 





How many different hamburgers is it possible to order? 
20080217 

Elizabeth pose la question : At a hamburger stand you can order a hamburger with any of the following, in any combination: ketchup, mustard, pickles, onions, tomatoes, mayonnaise and/or lettuce. How many different hamburgers is it possible to order? Penny Nom lui répond. 





What solid figure has 1 flat surface and 0 vertices? 
20080130 

Cheronda pose la question : What solid figure has 1 flat surface and 0 vertices? Stephen La Rocque and Harley Weston lui répond. 





Sides and vertices 
20071117 

derek pose la question : What is the correct name for a 2D geometric shape that would look like one slice from a round pizza and how may sides and vertices would it have? I believe you would say it has one vertex and two sides with the curved boundary not resulting in vertices or a side. Your help is much appreciated. Chris Fisher and Walter Whitelty lui répond. 





The best price for topsoil 
20071115 

Dawn pose la question : What is a better deal for topsoil, $150.00 for 10 cubic yards, $170.00 for 22 tons, or $200.00 for 11.5 yards? Penny Nom lui répond. 





A line between 2 vertices 
20071028 

robert pose la question : what do we call a line between 2 vertices which are not next to each other Walter Whiteley lui répond. 





Rolling a die repeatedly (you can't just add percentages) 
20071004 

Howard pose la question : If my son has a 16.66% chance of rolling a particular number on a dice,
and he rolls for it 6 times, he knows (from experience) that his
odds of getting at least 1 right are not 100% (16.66% +16.66%+16.66% etc).
He asked me if there was an equation that would give him the correct
percentage chance of success when trying X times for a Y% chance
of something. Victoria West lui répond. 





Cubic meters, square feet and office space 
20070925 

Kathryn pose la question : Can someone please help and let me know how do you convert 11 cubic meters into square footage? Steve La Rocque and Harley Weston lui répond. 





The diagonal of a square 
20070923 

Nasreen pose la question : A(7,2) and C(1,4) are two vertices of a square ABCD
find in the form ax+by=c the equation of the diagonal BD Stephen La Rocque lui répond. 





Vertices 
20070918 

Richard pose la question : Please help. Do not understand vertices, as in how many in a cone, hemisphere, etc. Harley Weston lui répond. 





How many vertices are there? 
20070910 

Makayla pose la question : I've just started the 4th grade and I am having trouble with a question on my homework. The questions is: Carrie is arranging sticks to make shapes. she has made a closed figure, with 10 sides How many vertices are there? I believe the answer is ten but I'm not sure. Stephen La Rocque and Walter Whiteley lui répond. 





Twenty dining tables 
20070813 

priya pose la question : Utkarsh bought 20 dining tables for Rs 120000 and sold these at a profit equal to the S.P of 4 dining tables.Find the S.P of one dining table.(give the answer in statements) Stephen La Rocque lui répond. 





Guessing multiple choice answers 
20070724 

carla pose la question : You are taking a multiple choice quiz that consist in 3 questions, each question has
3 possible answers only one is correct. To complete the quiz you randomly guess the answer
to each question . Find the probability of guessing exactly 2 answer correctly. b) at least to answer correctly . c)less than two answer correctly Stephen La Rocque lui répond. 





A triangular pyramid 
20070722 

shani pose la question : my homework question is confusing (yr 7 beginner)
"How many vertices does a triangular pyramid have."
(Mum thinks all triangles are triangular& vertices are sides)
I want to be sure. Penny Nom lui répond. 





Discount percentage 
20070711 

Greg pose la question : List Price: $50.00
Discount: 33 1/3%
What would the net price be? Stephen La Rocque lui répond. 





The probability of rolling double sixes twice in a row 
20070710 

Matt pose la question : what is the probability of rolling double sixes twice in a row? Stephen La Rocque lui répond. 





How fast was he going? 
20070603 

Mary pose la question : if a motorcycle left a 63 foot skid mark before hitting a car how fast was he going ? Penny Nom lui répond. 





The difference between two dice 
20070602 

smiley pose la question : Two standards dice are rolled. Determine the probability
that the difference between the two numbers on the dice is 2 Penny Nom lui répond. 





Hexagonal pyramids 
20070517 

Tracey pose la question : How many faces, edges, and vertices does a hexagonal pyramid have? Stephen La Rocque lui répond. 





What's a vertex? What's an edge? 
20070516 

Sophie pose la question : I don't understand what is a vertex and what is an edge. Please put a picture up and explain. I am a fifth grader. Brennan Yaremko and Steve La Rocque lui répond. 





The vertices of a triangle 
20070502 

natakie pose la question : Find the coordinate of the vertices of a triangle whose sides lie on the following three lines.
2x+5y16=0, 4x3y6=0 and 3x+y+2=0 Penny Nom lui répond. 





Vertices, edges and faces 
20070419 

Kimberly pose la question : I am trying to help my son find the vertices, edge, and face of a 16 sided figure.
I am not sure of the process to use to find these, could you please tell me
how to do this? Penny Nom lui répond. 





Which solid figure has 4 more edges than vertices? 
20070322 

dawn pose la question : which solid figure has 4 more edges than vertices? Penny Nom lui répond. 





Rolling two dice 
20070306 

Mary pose la question : I have a test and I need to know how to figure out how to find the probability of rolling 2 dice and coming up with a 7 for both rolls. Could you please explain how to find the probability? Thank you. Mary Penny Nom lui répond. 





What constitutes a face for a geometric solid? 
20070214 

Erica pose la question : What constitutes a face for a geometric solid? We have been getting conflicting answers from different textbooks. Some teachers are saying that cylinders and cones do not have faces. I'm thinking that cylinders have 2 and cones have 1. Please enlighten me. Thanks! Walter Whiteley lui répond. 





A margin of 19% 
20070201 

Ed pose la question : I PAY $10.95 FOR THIS PRODUCT, HOW SHOULD I PRICE IT IN ORDER TO HAVE A MARGIN OF 19% COST. Penny Nom lui répond. 





At the ice cream parlor 
20070110 

Bill pose la question : at the ice cream parlor, customers can chose among five different ice cream flavors and can choose either a sugar cone or a waffle cone. considering both ice cream flavor and cone type, how many distinct triplescoop with three different ice cream flavors are available? Penny Nom lui répond. 





A cylinder has how many flat surfaces, vertices, and edges? 
20070109 

Stacy pose la question : A cylinder has how many flat surfaces, vertices, and edges? Diane Hanson and Penny Nom lui répond. 





How many licence plates are possible? 
20061124 

Naomi pose la question : The state of New York has licence plates with five numbers followed by either a letter A or a letter B (eg. 36457A ,59972B ). How many licence plates are possible? Penny Nom lui répond. 





Lattice multiplication 
20061016 

Patti pose la question : I am a parent of a 5 th grader, and am a bit loss in the "new" math. I know how to multiply using the "old fashion" method. But, could you please explain lattice multiplication. Diane Hanson lui répond. 





A board is cut into two pieces... 
20060711 

DeAnna pose la question : A 102" board is cut into 2 pieces. One piece is two times the length of the other. Find the lengths of the two pieces. Stephen La Rocque lui répond. 





What is the probability that the policeman will shadow the correct person? 
20060614 

Kolby pose la question : Through an informer from the underworld, the police know the meeting place of a gang. The identity of the different gang members, however, is unknown. it is the duty of a policeman to shadow the leader of the gang. The policeman knows that the leader is the tallest of the five persons, all of whom have different heights. after the meeting, the gangsters, as a safety measure, leave the building separately at intervals of 5 minutes. As the policeman cannot see who is the tallest, he decides to let the first two gangsters go and shadow the one after that who is taller than all those who left before.Through an informer from the underworld, the police know the meeting place of a gang. The identity of the different gang members, however, is unknown. it is the duty of a policeman to shadow the leader of the gang. The policeman knows that the leader is the tallest of the five persons, all of whom have different heights. after the meeting, the gangsters, as a safety measure, leave the building separately at intervals of 5 minutes. As the policeman cannot see who is the tallest, he decides to let the first two gangsters go and shadow the one after that who is taller than all those who left before. What is the probability that the policeman will shadow the correct person? Steve La Rocque and Claude Tardif lui répond. 





What is the original cost? 
20060419 

Charlie pose la question : Selling a piece of furniture for $670 and the profit is 35%. What is the original cost? Stephen La Rocque lui répond. 





What is the cost price? 
20060414 

Purushotham pose la question : If the selling price is 120 and the profit is 20%, what is the cost price? Stephen La Rocque lui répond. 





Price percentages 
20060413 

Kristine pose la question : An item that is no longer on sale at "25% off" receives a price tag that is 33 1/3% more than the sale price. Has the item price been restored to its original price? Why or Why not? Stephen La Rocque lui répond. 





List price plus 10% 
20060403 

Heather pose la question : We shipped 2 pieces of an item with a unit price of $578.74 for a total amount of $1157.48. My task is to bill the customer at LIST + 10%. What formula do I need to use to calculate this? penny Nom lui répond. 





The square footage of an area in my backyard 
20060317 

Kim pose la question : I need to find out how to calculate the square footage of an area in my backyard that is in the shape of a "slice of pie". There are two sides that are straight lines that come together at the top to form a point, and then at the bottom is a curved line that joins the two other lines together. I need to figure out how to calculate the square footage that is inside the area. Penny Nom lui répond. 





A probability question which resulted from a game of Yahtzee 
20051231 

Robert pose la question : Could someone please assist me with this probability question which resulted from a game of Yahtzee we were playing in Melbourne, Australia on our holidays.
The object on this turn was to throw a “large straight” which is 5 numbers in sequence from 5 dice numbered 1 – 6. A player initially throws all 5 dice and then selects those dice they want to throw again for a further two more times. In this instance the player on their first throw, threw a 1,2,3,4 and 6.
Question: What is the respective probabilities of gaining a straight if they were to –
a) put back say the 6 and try and throw a 5 on the two further throws or…..
b) put back the 1 and 6 and try and throw a 1 and 5 or 5 and 6 on the two further throws bearing in mind that if one of the numbers was a 5 on the second throw they could hold that number and try for a 1 or 6 on the third throw.
I would be most appreciative if someone could assist in showing me how to calculate the probabilities particularly in the second instance (b). Penny Nom lui répond. 





Four 25sided dice 
20051124 

dan pose la question : Simply put, I am curious to find the likelyhood of each possibility (4100) if I were to roll 4 25sided die. It seems to start off simply, as 1, 4, 10, 20...following the inside diagonal of Pascal's triangle. But as soon as i reach the point where the sum is greater than the number of sides, Pascal's no longer seems to work. I would be greatly appreciated if I could be informed of the proper formula to find this answer, or perhaps if my theory of doing it is wrong. Andrei Volodin and Shaun Fallat lui répond. 





I need to know the measurement of 75grams of spice into milliliters. 
20050916 

Cyla pose la question : I don't know if this is possible but I need to know the measurement of 75grams of spice into milliliters. Even an approximation would be great. Penny Nom lui répond. 





Who is taller: John or Mary? 
20050914 

Ulises pose la question : All the students in a school are arranged in a rectangular array. After that, the tallest student in each row was chosen, and then among these John Smith happened to be the shortest.Then, in each column, the shortest student was chosen, and Mary Brown was the tallest of these. Who is taller: John or Mary? Penny Nom and Claude Tardif lui répond. 





A melting ice sphere 
20050709 

A student pose la question : A 2 meter diameter sphere of ice melts at 1.5 millimeters per minute. How many minutes will it take to fill up a hexagonal container measuring 1.5 meters on a side, and 0.8 meters deep? Penny Nom lui répond. 





Cost price 
20050525 

Sunitha pose la question : What is (how to calculate) the cost price of a product which is markedup by 15% and retailed at $25? Penny Nom lui répond. 





A matrix problem 
20050404 

Alan pose la question :
Let A = 

1  1  0 

2  1  2 
a  b  c 
where a, b, c are constant real numbers. For what values of a, b, c is A invertible? [Hint: Your answer should be an equation in a, b, c which satisfied if and only if A is invertible.]
Judi McDonald lui répond. 





Two matrix problems 
20050330 

Sue pose la question : Question 1
Suppose all matrices in the equation below are square and invertible. Solve for x .
BA1XB1 + 2BA + In = 0 (the symbol "0" here denotes the matrix of all 0's in it)
Also, A1 or B1 is indicating inverse and "In" = for example, A1 times A
I hope you understand the above. I have to show all the steps.
Question 2
Suppose we consider the set of all 2x2 matrices along with the operations of matrix addition and multiplication. Do they form a field? Why or why not?
I think the answer is no because under multiplication it is not commutative and not all square matrices are invertible. I not positive so I'd like some help. Penny Nom lui répond. 





A matrix construction problem 
20050314 

Marcelo pose la question : I want to know if is it possible to solve this problem:
I have an empty NxM matrix and I know totals (sum) by rows and totals by column.
Is there any algorithm to fill the matrix so that the summary of columns and rows gives the original values I have? Harley Weston lui répond. 





Strings of 4 digits from 1,2,...,7 
20041209 

Tom pose la question : How many different combinations can be made of the numbers 17 in 4 string combinations in any order? EX:7235, 3517, etc...
And if you were to include the same 2 numbers in every combination, how many would that make? EX: Using 1 & 2: 1274, 5142, 2751, etc... Penny Nom lui répond. 





The price of a book 
20040918 

Dorly pose la question : If the number of toonies required to buy a book is nine more than the number of
fivedollar bills required to buy the same book, determine the cost of the book. Penny lui répond. 





A pyramid 
20040511 

Quiana pose la question : I am a student and I have the following questions I need to answer for homework:
How many sides, vertices, and edges does a pyramid have? Penny Nom lui répond. 





Three dice 
20040510 

A student pose la question : If one has 3, 6 sided dice what is the probability of the numbers that are rolled to total 4 through 10 inclusively?
Subsequent to this, what is the probability to do this consecutively...say 3 times? Peny Nom lui répond. 





Arrays 
20040219 

A parent pose la question : please demonstrate mathematical arrays fro a 3rd grader Penny Nom lui répond. 





Matrices 
20031205 

Julie pose la question : I am doing a project and need to find some mathematiciens who had an influence in matrices. I can't seem to find any when I search online. Could you please help me with this? Judi McDonald lui répond. 





The mean house price 
20030910 

Carol pose la question :
Question: I have to find the mean from the following example: Price Range £000  No of Houses  55 and under 60  3  60 and under 65  6  65 and under 70  13  70 and under 80  21  80 and under 100  15  100 and under 130  7  130 upwards  1  I know when calculating the mean you use the mid points of the classes, but how does this work for the 130 upwards class? Also, does this still work given the difference in the classes (ie. 1st class is 5, 5th class is 20, etc). Any help to get me started would be greatly appreciated. Penny Nom lui répond. 





An onsale DVD player 
20030709 

Kim pose la question : I have a DVD player with a regular selling price of $175 and percentage of discount is 10 percent. How to solve for discount amount and sale price? Also, when you figure out the sale price how to figure out commission amount when percentage of commission is 5 percent? Penny Nom lui répond. 





8 faces, 12 vertices, and 18 edges 
20030422 

Thomas pose la question : I would like to know the proper name for this geometrical solid. It has 8 faces, 12 vertices, and 18 edges? Penny Nom lui répond. 





A determinant 
20030213 

A student pose la question :
I have to find the determinant of the following matrix 2  3  1  2  4  3  0  2  5  1  4  2  1  3  5  2  3  4  1  2  6  0  3  2  4  Penny Nom lui répond. 





A house's selling price 
20021105 

Tanisha pose la question : a CERTAIN REALESTATE AGENT RECEIVES $6 FOR EVERY $100 OF A HOUSE'S SELLING PRICE. HOW MUCH WAS A HOUSE SOLD FOR IF THE AGENT $10,725._ Penny Nom lui répond. 





A sale price 
20021015 

Chester pose la question : A jacket is on sale for 32% off. Find the original if the sale price is $89.00 Penny Nom lui répond. 





Tree diagrams 
20021012 

Denean pose la question :
 For lunch, students can choose juice or milk; hamburger or pizza; and a banana or apple. How many lunch combinations can the students make?
 In an experiment, Monty can use paper towels or cloth. He can choose red, green, or yellow food coloring. How many combinations are there?
Penny Nom lui répond. 





A game of dice 
20020513 

Mika pose la question : To play a game a dice is rolled to see who plays first. four players are going to play the game. what is the probability that at least two people roll the same number? ANSWER: P(least 2 people roll the same #)=number of player/total outcome P = 4!/4C2 = 24/4C2 = 4 the answer is 40% Andrei Volodin lui répond. 





A probability tree 
20020504 

A student pose la question : Karl and Naomi roll three dice. Karl gives $10 to Naomi if the number 5 turns up once, twice or three times. Naomi gives Karl $3 in all other cases. A) construct the probability tree for this situation.
B) Does Karl have an advantage in this game? Justify your answer. My problem is I am unfamiliar on how to draw this probability tree and seem to be having a lot of difficulties, when you have a chance please answer this math problem and get back to me with the results. Penny Nom lui répond. 





If you conect all the vertices of a regular ngon... 
20020401 

Murray pose la question : If you conect all the vertices of a regular ngon with lines you will have (n3)(n/2) lines inside the polygon. I want to find out how many sections these lines divide the polygon into and how many intersections they have with each other. Claude Tardif lui répond. 





Rolling 5 sevens before rolling a six or an eight 
20020120 

Tony pose la question : When rolling 2 dice, what is the probability of rolling 5 sevens before rolling a six or an eight? Andrei Volodin and Penny Nom lui répond. 





A sale on eggs 
20020117 

A student pose la question : A store had a sale on eggs, selling 13 eggs for the usual price of a dozen eggs. As a result, the price of the eggs was reduced by 4 cents a dozen. What is the original price for a dozen eggs? Penny Nom lui répond. 





Matrix 
20011121 

Hoda pose la question : I have a question about matrix multiplication; well, actually, matrix division. I am assuming that matrices are divided the same as they are multiplied; that is, row by column. But what happens if you have to divide by zero? How does this affect the resulting matrix? Patrick Maidorn and Penny Nom lui répond. 





Free pamphlets 
20011024 

Salman pose la question : a travel agency has limited number of six different free pamphlets about the beetle islands. the agent tells you to take any that you want, but not more than two of any kind. Assuming that you take at least one pamphlet, how many choices could you make Penny Nom lui répond. 





15 mice in 4 cages 
20011008 

Chelsea pose la question : How can you fit 15 mice into 4 cages with an odd number of mice in each cage? Claude Tardif and Harley Weston lui répond. 





Rolling two dice 
20010910 

Owen pose la question : This probability question has been bugging me for a while. Two ordinary dice are rolled. If it is known that one shows a 5, what is the probability that they total 8? I have two different but (seemingly) correct solutions. Andrei Volodin lui répond. 





Vertices 
20010808 

Jordan pose la question : I am a fifth grader learning geometry with my mom's help, can you please explain what a vertices are?? Penny Nom lui répond. 





Conformable matrices 
20010805 

Wayne pose la question : Can someone explain the concept of conformable matrices in a way that is easy to understand ? One definition says to multiply matrices rows and columns must conform, ie, 5 x 3 matrix times a 3 x 5 matrix. In the next example, however a 8 x 1 matrix and a 8 x 3 matrix are said to be conformable! Steve Kirkland lui répond. 





Matrix reconstruction 
20010719 

Guy pose la question : Is there a way to get the sums of rows, columns and diagonals of an n x n matrix to reconstruct the original matrix? Walter Whiteley and Patrick Maidorn lui répond. 





Mutually exclusive 
20010605 

Marje pose la question : What does the mathmatical term "mutually exclusive" mean. Pleas diagram if possible. Penny Nom lui répond. 





Probabilities and dice. 
20010504 

Carmen pose la question : Hi! My name is Carmen! I am a member of a grade 5 class in Edmonton, AB. We were talking about probability in math, and I was wanted to know what the probability (odds) of rolling two sixes would be rolling two dice? If it is not to diffucult could you tell me what the probability (odds) of rolling any number with two dice were? Andrei Volodin and Penny Nom lui répond. 





Expected value 
20010424 

Cindy pose la question : A game consists of rolling a single fair die. If a number great than 4 is rolled you win the number of dollars showing on the die. If any other number is rolled, you receive $1.00. What is the expected value of this game? Andrei Volodin lui répond. 





Oil revenue 
20010421 

Brian pose la question : Suppose that t months from now an oil well will be producing crude oil at the rate of r(t), not a constant, barrels per month and that the price of crude oil will be p(t), not a constant, dollars per barrel. Assume that the oil is sold as soon as it is extracted from the ground.  Find an expression for the total revenue from the oil well, R(t).
 A certain oil well that currently yields 400 barrels of crude oil a month will run dry in 2 years. The price of crude oil is currently $18 per barrel and is expected to rise at a constant rate of 3 cents per barrel per month. What will be the total revenue from this well? {Hint: Model the degraded production rate with the equation:
r(t) = (ABt)e^{0.04t}} Harley Weston lui répond. 





Matrices 
20010326 

Peg pose la question : What are some applications of matrices, basic trigonometry, and linear systems in the real world? I'm writing and Algebra report about where these topics are used outside of the classroom. Judi McDonald and Walter Whiteley lui répond. 





Solving Equations 
20010223 

Stephanie pose la question : Do you know who came up with solving equations? Do you have any websites that can give me good information on solving equations? Do you know any history on solving equations? Do you know what solving equations is used for? And finally............Sorry about all of the questions :) Has the form of solving equations changed from the time it came out to now? Juci McDonald lui répond. 





Conditional probabiity 
20010122 

Wallace Yang pose la question : A pair of sixsided fair dice is thrown. Find the probability that the sum is 10 or greater if it is given that a 5 appears on at least one of the dice. Penny Nom and Claude Tardif lui répond. 





The city transit system 
20010107 

Jacky pose la question : The city transit system carries an average of 9450 bus riders a day, for a fare of $1.75 each. The city wants to reduce car pollution by increasing ridership and to maximize the transit system's revenue at the same time. A survey indicates that the number of riders will increase by 150 for every $0.05 decrease in fare. Harley Weston lui répond. 





Three dice 
20010103 

John Read pose la question : I have three dice (A, B, C.) Three sides of each dice are blank. Three sides of each dice have a number. When the dice are thrown, it must be possible to result in the numbers 1 to 49 in any combinations without doubling up on any figure. i.e. Different combinations resulting in the same end number. I managed to get from 1 to 47 before getting stuck. Claude Tardif lui répond. 





Euler's Formula 
20001111 

Denise Roberts pose la question : I'm trying to design a unit (possibly involving a Webquest) on Polyhedra and I cannot find a formula I once used. The formula involved the number of vertices (V), edges (E), and faces (F) of the polyhedra. Walter Whiteley lui répond. 





Where will we use this in the real world? 
20001011 

Jane Ann Musgrove pose la question : As a teacher of mathematics, I am always asked "Where will we use this in the real world?". I am seeking ideas/sites via the internet where students can find answers to this type of question. Can you help me? To be more specific, right now I am interested in finding careers where the employees would use the concepts of "Radicals", "Matrices", and "Logarithms". This information will be used by students to make presentations to the class on their findings from internet searches. Harley Weston lui répond. 





Review problems 
20000918 

Dee pose la question : A card is selected from an ordinary deck of cards. What is the probability of. . . selecting 2 aces in a row? If you toss two dice, what would be your probability of the following? . . . Penny Nom lui répond. 





A matrix equation 
20000514 

A student pose la question : Right now, we are dealing with matrices and we are supposed to solve the following problem on our graphingcalculators: 2a+3b4c+d=20 a2b+3c5d=14 3a+4b2c+3d=19 5ab+6c+4d=5 Penny Nom lui répond. 





Matrices Information 
20000502 

William Avery pose la question : I am an OAC student at Governor Simcoe Secondary School in St. Catharines Ontario. Today at school we were handed an independent study project by our Finite teacher. This assignment is based on Matrices, it involves performing some simple matrix calculations, but also involves a written section. This written section asks for the following: . . . Marley Weston lui répond. 





Taxis in Chicago 
20000327 

A high school studenthigh school student pose la question : Suppose that taxis pick up and deliver passengers in Chicago, which is divided into three zones. Records kept by the drivers show that of the passengers picked up in Zone 1, 50% are taken to a destination in Zone 1, 40% to Zone 2, and 10% to Zone 3. OF the passengers picked up in Zone 2, 40% go to Zone 1, 30% to Zone 2, and 30% to Zone 3. Of the passengers picked up in Zone 3, 20% go to Zone 1, 60% to Zone 2 and 20% to Zone 3. Suppose that at the beginning of the day, 600 of the taxis are in Zone 1, 100 in Zone 2, and 300 in Zone 3. What is the distribution of taxis in the various zones after all have had two riders? Harley Weston lui répond. 





A Multiple Choice Test 
19990831 

Cintra Ramnarine pose la question : I have ten questions. There are two multiple choice answers to each question. What are the chances of answering all questions correctly. Harley Weston lui répond. 





Matricies 
19981126 

Stephanie Webster pose la question : If a matrix for a rectangle looks this way: AACC BDDB What does the matrix for a square look like? Penny Nom lui répond. 





Three dice 
19981117 

Ryan Allinson pose la question : Rolling three regular dice how many different ways could a sum of 10 be rolled? Hope you can help. Can you please show me how this is done? Penny Nom lui répond. 





Snake Eyes 
19980720 

Would you please advise me what the probability is of rolling snake eyes on a pair of dice is? My recollection is 1 out of 6 multiplied by 1 out of 6 = 1 out of 36 is this correct? Jack LeSage and Penny Nom lui répond. 





Rolling a seven 
19980611 

Bruce Thompson pose la question : What is the probablity of rolling two dice and it coming out as seven? a) 1/6 b) 1/36 please give me the correct awnser and explain please. Harley Weston lui répond. 





Mathematical Arrays 
19980501 

Gene Lanctot pose la question : Could someone please explain what a mathematical or arithmetical array is? The array in question is used in grade three math in Ontario. I would also like to know what its purpose is. Harley Weston lui répond. 





Matrices 
19980310 

Ksya pose la question :
 A and B are matrices. If A^n=B^n, can we say A=B or det(A)=det(B) or det(A)^n=det(B)^n ? Any conditions ???
 If B^(1) is the inverse of B, where B is a matrices. Can we say [(B^(1))^n][B^n]=I, where I is identity matrices? Any conditions???
Doug Farenick lui répond. 

