GMATPrep: DS problem

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GMATPrep: DS problem

by kookoo4tofu » Mon May 07, 2007 12:18 pm
Not sure how to do this one. please help! thanks.

If x and y are positive integers, what is the value of x + y?
(1) (2^x)(3^y) = 72
(2) (2^x)(2^y) = 32

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Re: GMATPrep: DS problem

by jayhawk2001 » Mon May 07, 2007 8:58 pm
kookoo4tofu wrote:Not sure how to do this one. please help! thanks.

If x and y are positive integers, what is the value of x + y?
(1) (2^x)(3^y) = 72
(2) (2^x)(2^y) = 32
Is it D?

1 - sufficient. 2^x*3^y = 2^3*3^2 = 72. Therefore x+y = 3+2

2 - sufficient. 2^(x+y) = 2^5. x+y = 5

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by Stacey Koprince » Tue May 08, 2007 11:42 am
Yep - break down the right sides of the equations to have the same bases!
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