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One one |
2003-04-22 |
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From Brad:
find the next two rows of numbers?
1
1 1
2 1
1 1 1 2
3 1 1 2
1 1 1 2 1 3
Answered by Leeanne Boehm. |
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The effectiveness of a drug |
2003-04-22 |
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From A student:
A certain drug is found to be effective 80% of the time. Find the probability of successful treatment in two out of four cases.
Answered by Andrei Volodin. |
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Manipulating exponents |
2003-04-21 |
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From Denita:
Rewrite using only positive exponents:
(4a^4b^2)^4 * (4a^ -3 bc^2)^ -3
Answered by Harley Weston. |
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Chopping trees |
2003-04-19 |
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From Tamara:
The master needs some of the trees (twenty, to be exact) at the back of his spooky old mansion cleared to make way for a new evil laboratory, so he decides to send some his slaves to do the work for him. He initially sends out four of his men, armed with axes, to chop the trees down. Due to the fact he is very impatient, every ten minutes he sends out another man to help with the work. Assuming that it takes one man 30 minutes to chop down 1/3 of a tree, how long till all twenty trees are chopped down?
Answered by Penny Nom. |
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A tangent to a circle |
2003-04-18 |
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From Lech:
The line with equation y=mx is a tangent to the circle with equation x2+y2-6x-6y+17=0. Find the possible values of m.
Answered by Harley Weston. |
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Interest compounded daily |
2003-04-18 |
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From Bruce:
I recently received $7,987.68. This amount consisted of $7,543.61 invested at 6% per annum, compounded daily. I am trying to find out how many days this investment accrued interest.
Answered by Penny Nom. |
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The substitution method |
2003-04-14 |
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From Patty:
I need help with the following: 5x - 4y = 13 2y + 3x = -1
Answered by Penny Nom. |
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The square of my age was the same as the year |
2003-04-14 |
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From Pat:
Augustus de Morgan wrote in 1864, "At some point in my life, the square of my age was the same as the year." When was he born?
Answered by Penny Nom. |
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Area of a trapezoid |
2003-04-13 |
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From A road builder:
My husband works with asphalt building roads. There are times when one end of the road will be (for example) 100ft wide the other end would be( for example) 200ft wide and he must figure the area in square feet. So far it has been a guessing game because he dosen't have the formula to figure the square feet.
Answered by Penny Nom. |
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Incremental standard deviation |
2003-04-12 |
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From Carlos:
I need to calculate the standard deviation for a group of data, but I don't know in advance what is the mean. Is there a way to adjust the STDV for each datum without keeping all of the previous values? This is needed basicaly for performance, so I won't need to read twice the same data (spend processing time) nor save the previous values (spend memory).
Answered by Andrei Volodin and Penny Nom. |
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Soustraction avec les heures |
2003-04-08 |
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From Jennifer:
Je m'appelle Jennifer et malheureusement j'ai un petit souci. Pour le calcul des heures c'ets à dire je ne me rappelle plus comment s'effectue une addition ou un soustraction avec les heures comme par exemples 9h45-7h52. Si vous pouviez m'aider j'ens erais trés contente.
Answered by Diane Hanson and Claude Tardif. |
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A fractional inequality |
2003-04-08 |
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From Jessica:
Solve for x. Write in interval notation.
[(x2)-9]/[x-5] >= 0
Answered by Penny Nom. |
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Un polyedre convexe |
2003-04-07 |
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From Hubert:
quelle sont les conditions nécessaire pour former un polyedre convexe avec un seul type de polygone?
Answered by Claude Tardif. |
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The surface area of a cube |
2003-04-07 |
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From Sarah:
if the volume of a cube is 64 cm, then what's the total surface area? I also want to know how to show my work.
Answered by Penny Nom. |
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Jo's books |
2003-04-07 |
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From Miguel:
Jo announces, "I have more than 999 books."
Jean says: "No Jo! You have fewer than 1,000 books."
Mary says: "Jo has at least 1 book."
Only one of these statements is true. How many books does Jo own?
Answered by Penny Nom. |
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