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A boat weighs 1500 lb more than its motor ... |
2005-10-17 |
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Dimitri pose la question :
A boat weighs 1500 lb more than its motor and 1900 lb more than its trailer. Together the boat and motor weigh five times as much as the trailer. How much does the boat weigh?
Penny Nom lui répond. |
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Arrays |
2005-10-17 |
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Danette pose la question :
My son's fourth grade workbook is asking him to draw four possible arrays for 72 marbles.
I don't understand what they mean
Penny Nom lui répond. |
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Divisibility by each of the first ten counting numbers |
2005-10-17 |
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Simon pose la question :
determine smallest positive integer that is divisible by each of the first ten counting numbers
Penny Nom lui répond. |
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A random sample |
2005-10-16 |
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Stu pose la question :
If I have a set of data points (14 to be exact)of unknown pedigree from a large population, what tests can I apply to see if they constitute a random sample from the large population?
Andrei Volodin and Penny Nom lui répond. |
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2x - 5x + 6.3 = -14.4 |
2005-10-16 |
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Leslie pose la question :
How do we solve 2x - 5x + 6.3 = -14.4
Penny Nom lui répond. |
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How many gallons will it hold? |
2005-10-16 |
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Scott pose la question :
I am building a pond and need to convert the cubic dimensions into gallons in order to know what size fountain pump to purchase.
My pond is 1 foot deep x eight feet long x three feet wide.
How many gallons will it hold?
Penny Nom lui répond. |
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What is the sum of the measures of the angles of a decagon? |
2005-10-15 |
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Dianna pose la question :
What is the sum of the measures of the angles of a decagon?
Penny Nom lui répond. |
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How many pixels are there to an inch? |
2005-10-15 |
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Fred pose la question :
I want to know how many pixels there are to an inch.
Penny lui répond. |
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How would I find the length of the radius? |
2005-10-15 |
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Stace pose la question :
If given the length of a chord (121") and the distance from the midpoint of the arc to the midpoint of a chord (12"), how would I find the length of the radius?
Penny Nom lui répond. |
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The area of an irregular semi-circle |
2005-10-14 |
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Bob pose la question :
Is there a way to compute the area of an irregular semi-circle i.e. one in which the arc length is not determined by the diameter; and is therefore not technically any part circular - yet still possessing an arched side?
Penny Nom lui répond. |
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Determine the height |
2005-10-14 |
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Paul pose la question :
if you know the distance to the base and the angle to the top how can you determine the height
Penny Nom lui répond. |
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The coefficient of thermal expansion for steel |
2005-10-14 |
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Jim pose la question :
Is the following statement true?
“The coefficient of thermal expansion for steel is 0.00000645in/in/deg. Doesn't sound like much but when you run out the numbers it comes to .405504 ft/mile/deg. Still doesn't sound like much, only about 5". Then multiply by 40 degrees and you get a piece of rail that has grown by 16.22 feet in that one mile. It's not at all unusual for the rail temp to go from say, 40 deg to 80 deg on a spring or fall day. Remember that on a sunny day, the rail temp can be significantly higher than the air temp as well."
I ran the math and came up with an answer closer to 16 inches, instead of 16 feet. Which is closer to being correct?
Penny Nom lui répond. |
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Simultaneous equations |
2005-10-13 |
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Daniel pose la question :
5x + 3y = 22
4x - 7y = -20
Penny Nom lui répond. |
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The bathtub curve |
2005-10-13 |
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David pose la question :
My father asked me to submit a question about the so-called 'bathtub
curve'. If you cut a bathtub in half lengthwise down it's middle, the
edge of the tub would describe the 'bathtub curve' which can be used
to demonstrate typical failure rates of products. This curve is
characterised by high initial (infant mortality) failure rates at
it's beginning, which drop quickly to a very low level. Failures then
increase gradually to the "end of life" stage where the failure rate
takes off dramatically again.
If anyone in the math department knows about the so-called 'bathtub
curve' my father would really appreciate the equation.
Chris Fisher and Edward Doolittle lui répond. |
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Means of sample means |
2005-10-12 |
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Fareeha pose la question :
A population consists of six numbers 1,2,3,4,5,6
a) How many different samples of two numbers can be selected with replacement? and list them.
b) Calculate the mean and standard deviation of the population
b2) Calculate the mean and standard deviation of the mean of the samples.
c) Find the standard error of your estimated mean in question b2 and compare with the estimated standard deviation in b2.
Penny Nom lui répond. |
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