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A probability density function |
2004-04-14 |
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A student pose la question :
The label on a bottle of liquid detergent shows contents to be 12 ounces per bottle. The production operation fills the bottle uniformly according to the following probability density function:
f(x) = 8 for 11.975 <= x <= 12.10
and
f(x) = 0 elsewhere
a. What is the probability that a bottle will be filled with 12.02 or more ounces?
b. What is the probability that a bottle will be filled between 12 and 12.05 ounces?
c. Quality control accepts production that is within .002 ounces of number of ounces shown on the container label. What is the probability that a bottle of this liquid detergent will fail to meet the quality control standard?
Penny Nom lui répond. |
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A geometric sequence |
2004-04-13 |
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Michael pose la question :
In a geometric series, the sum of the 2nd and 3rd terms is 60, and the sum of the 3rd and 4th terms is 240. Find the sum of the first 7 terms.
Penny Nom lui répond. |
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Circles in a hexagon |
2004-04-11 |
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Crystal pose la question :
step by step can you show me how to calculate the area of the region inside the hexagon but outside the seven circles. given the radius of each circle is one inch
Penny Nom lui répond. |
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Percent difference |
2004-04-10 |
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A parent pose la question :
For a school science project, my son Alex is taking measurements of plant growth at regular intervals. As part of the data, he must provide the maximum percent difference observed in the categories his team has identified.
So, for example he has six plants with four measurements each. (He has more, but I'll keep it simple) For the first plant he measured 2mm, 2.4mm, 2.9mm, and 3.2mm. For the 2nd, 3rd, and 4th plants, he has similar numbers. Is there a way to calculate the maximum percent difference between any two plants in his measurements during the project? Doing it for each combination would be tedious.
Penny Nom lui répond. |
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Snow in the driveway |
2004-04-09 |
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Patricia pose la question :
Following a severe snowstorm, Ken and Bettina Reeves must clear their driveway and sidewalk. Ken can clear the snow by himself in 4 hours, and Bettina can clear the snow by herself in 6 hours. After Bettina has been working for 3 hours, Ken is able to join her. How much longer will it take them working together to remove the rest of the snow?
Penny Nom lui répond. |
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What is the nth term |
2004-04-07 |
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Jason pose la question :
1 4 10 20 35 56 84
what is the nth term
Claude Tardif lui répond. |
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Rational expressions |
2004-04-06 |
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Shivani pose la question :
I am in 11th grade Honors Algebra II. We are currently learning about adding and subtracting rational expressions. I looked at the other questions that were similar to that of mine, but they weren't quite answering my question. I have been working on many problems to practice and see if I can come up with the correct answer, but I can't, I got like 2 out of every 7 right on my school homework. I get the easy ones, where when you have to find the LCD, it's just the other denominator. But, on others you have to really think about it. Those are hard. Here are some of the problems that I cannot get at all: (x2 - 3x + 1)/(x2 - 4) - (x2 + 2x +4)/(2 - x) - (x - 4) /(x - 2)
The correct answer is:
(x3 + 4x2 + 7x + 17)/(x2 - 4)
Penny Nom lui répond. |
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The sum of angles in a triangle |
2004-04-06 |
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A student pose la question :
How can u prove sum of angles in a triangle equal to 180 degrees?
Penny Nom lui répond. |
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Differences in percentages |
2004-04-06 |
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Jose pose la question :
Question:
You have two groups:
Group A has 10 people and 2 are Chinese
Group B has 12 people and 3 are Chinese
In terms of percentages what is the difference in Chinese between the two groups? In other words which group has the biggest percentage of Chinese and why?
Penny Nom lui répond. |
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Trisecting an arbitrary angle |
2004-04-06 |
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Joe pose la question :
Where can I submit my effort on trisecting an arbitrary angle with only a straightedge and a compass? I can do it but I do not have the smarts to prove it.S
Chris Fisher lui répond. |
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Ratios |
2004-04-05 |
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Tim pose la question :
The ratio of W to H was 7 to 9. The ratio of H to I was 9 to 5. If the sum of the W and H exceeded twice the number of I by 12, how many were W, how were H and how many were I?
Penny Nom lui répond. |
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x^2/3 - 7 x^1/3 + 12 = 0 |
2004-04-05 |
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Jackie pose la question :
I am having trouble solving this question for x:
1.) x^2/3 - 7 x^1/3 + 12 = 0
Penny Nom lui répond. |
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(3x50)+20/5=? |
2004-04-03 |
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A student pose la question :
what is the answer to:
(3x50)+20/5=?
Penny Nom lui répond. |
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A changing rectangle |
2004-04-03 |
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A student pose la question :
The width x of a rectangle is decreasing at 3 cm/s,
and its length y is increasing at 5 cm/s. At what rate
is its area A changing when x=10 and y=15?
Penny Nom lui répond. |
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Ratio and proportion |
2004-04-02 |
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Kenneth pose la question :
The terms of a ratio in a proportion are often expressed as a is to b as c is to d.
Example: 2/4 = 6/12 this proportion represents that 2 is to 4 as 6 is to 12.
What does the "a is to b as c is to d" really represent or indicate in ratios?
Claude Tardif lui répond. |
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