Math questions from any Manhattan Prep GMAT Computer Adaptive Test.
relansachin
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The Power of Absolutes

by relansachin Sat Sep 25, 2010 7:20 am

If a and b are integers and a is not equal to b, is ab > 0?

(1) a^b > 0

(2) a^b is a non-zero integer


I got the answer E, is it correct ?
gokul_nair1984
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Re: The Power of Absolutes

by gokul_nair1984 Sat Sep 25, 2010 7:39 am

Yes the answer has to be E. Let me know if you need the explanation.
relansachin
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Re: The Power of Absolutes

by relansachin Sat Sep 25, 2010 7:53 am

gokul_nair1984 Wrote:Yes the answer has to be E. Let me know if you need the explanation.



Thanks gokul it would be great if you can post the explanation as well !!
gokul_nair1984
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Re: The Power of Absolutes

by gokul_nair1984 Sat Sep 25, 2010 1:33 pm

Here you go:

If a and b are integers and a is not equal to b, is ab > 0?

(1) a^b > 0

(2) a^b is a non-zero integer

For Statement 1, substitute
Let a=2 and b=3...So 2^3=8, which is greater than 0. ab=6. Thus ab>0.
Let a=-2 and b=2..So (-2)^2=4, which is greater than 0. ab=-4.
Thus ab<0.
Hence A is insufficient.

You can substitute the same values for a and b to disprove B as well.

Combining both Statements, again use the same numbers
(infact, you don't need to do this) and you'll find C to be insufficient.

So E is the answer
tim
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Re: The Power of Absolutes

by tim Fri Oct 08, 2010 1:04 am

:)
Tim Sanders
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