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The Mean Value Theorem |
2001-07-23 |
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From Corrie:
I need to find if the mean value theorem exists. and if so, find all values c guaranteed by the theorem. f(x) = |x2-25| on the interval [-10,0]
Answered by Harley Weston. |
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What did the girls score on average? |
2001-07-20 |
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From Rajesh:
The students of two schools were sitting the same test. The students attending the first school scored 74 on average; within this the average scores of the boys and the girls were 71 and 76, respectively. The corresponding scores in the other school were 84, 81 and 90, respectively. If the average score of all boys was 79, what did the girls score on average?
Answered by Penny Nom. |
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Matrix reconstruction |
2001-07-19 |
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From Guy:
Is there a way to get the sums of rows, columns and diagonals of an n x n matrix to reconstruct the original matrix?
Answered by Walter Whiteley and Patrick Maidorn. |
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Hours worked |
2001-07-18 |
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From Carlos:
I have a simple question:whats the formula to transform time into decimals? more exactly im working on a spreadsheet and i want to be able to type in for example hours worked: 11- 11:30 pm and a formula would tell me 12.5 hours how do i do it?
Answered by Patrick Maidorn. |
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Generating uniquie 2 digit numbers |
2001-07-16 |
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From Anthony:
What methodology can I use to generate uniquie 2 digit numbers from unique 7 digit numbers. Of'course the total number of 7-digit numbers is not greater than 99.
Answered by Penny Nom. |
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Rhombus |
2001-07-16 |
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From William:
Calculate the internal angles of a rhombus given measurments of all four sides only.
Answered by Walter Whiteley. |
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Margin of error |
2001-07-13 |
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From Jim:
If a survey was completed by four different groups of people as indicated below what would the over-all margin of error be for this survey given the fact that the number of people in each group were different?
Group # polled Margin of error
A. 779 +/- 4%
B. 315 +/- 7%
C. 323 +/- 6%
D. 254 +/- 9%
Answered by Andrei Volodin. |
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6,000,000,000,000,000,000 |
2001-07-12 |
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From James:
How would I express 6,000,000,000,000,000,000 in words?
Answered by Leeanne Boehm. |
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The speed of the boat |
2001-07-12 |
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From Sharon:
A motor boat is travelling in a southeasterly direction in water that is flowing from the south at 2km per hour. Show that the speed of the boat is (6 times the square root of 2) km per hour, given that it can travel at 10km per hour in still water.
Answered by Penny Nom. |
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Comparing means and standard deviations |
2001-07-11 |
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From Shelly:
Is there a way to compare means and standard deviations that come from different size samples? Is there an equation that can normalize sample size?
Answered by Andrei Volodin. |
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Investing $5,000 |
2001-07-09 |
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From A student:
A principal amount of $5,000 was invested in a savings account for 5 years.The interest earned was $500.Use the simple interest formula to find the annual rate of interest.
Answered by Penny Nom. |
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Cakes and ribbons |
2001-07-05 |
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From Jennifer:
- A cake recipe calls for 3 1/4 cups of flour. You already put in 1 3/4 cups. How much more should you add?
- You have 3/4 yard of ribbon. How many 1/8-yard pieces can you cut the ribbon into?
Answered by Penny Nom. |
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Some irrational numbers |
2001-07-03 |
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From Kellie:
- Is it possible to write pi as a fraction?
- Is it possible to write the square root of 2 as a fraction.. Explain why?
Answered by Harley Weston. |
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Arclength of an ellipse |
2001-07-03 |
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From A hobbyist:
What is the equation (with the length of the arc as a variable) for one quadrant of the ellipse,...
Answered by Claude tardif. |
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A confidence interval |
2001-06-28 |
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From Murray:
An investigator wants to find out of there are any difference in "skills" between full and part time students. Records show the following:
Student Mean Score Std Dev Number
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Full time 83 12 45
Part time 70 15 55
Compute a 95% confidence interval for the difference in mean scores.
Answered by Andrei Volodin. |
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