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pt questions

by jc114 » Mon May 07, 2007 7:23 am
If x and y are positive numbers and z=xy^2, a 50 % increase in x and a 20% decrease in y would result in which of the following changes in z?
A. decrease of 4%
B. decrease of 14%
C. increase of 4%
D. increase of 20%
E. increase of 30%

If n is an integer, which of the following cannot be a factor of 3n+4?
A. 4
B. 5
C. 6
D. 7
E. 8
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by mschling52 » Mon May 07, 2007 7:40 am
(1) A - decrease of 4%

50% increase in x = 1.5x
20% decrease in y = 0.8y

Plug these into the equation for z (z=xy^2) and we have

1.5x*(0.8y)^2 = (1.5)(0.64)xy^2 = 1.5(0.64)z = 0.96z,

so we have a 4% decrease in z.
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by Cybermusings » Mon May 07, 2007 9:28 am
If x and y are positive numbers and z=xy^2, a 50 % increase in x and a 20% decrease in y would result in which of the following changes in z?
A. decrease of 4%
B. decrease of 14%
C. increase of 4%
D. increase of 20%
E. increase of 30%

If n is an integer, which of the following cannot be a factor of 3n+4?
A. 4
B. 5
C. 6
D. 7
E. 8

In the first question there should be an decrease of 4%
For the second question its not possible for 6 to be a factor of 3n+4
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