number greatest

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number greatest

by gayu » Sat May 07, 2011 10:58 pm
which of the following is greatest?

A)(1/5)^ -2 B)(1/3)^ -2 C)3^ -2 D)5^ -2 E)2^3

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by manpsingh87 » Sat May 07, 2011 11:11 pm
gayu wrote:which of the following is greatest?

A)(1/5)^ -2 B)(1/3)^ -2 C)3^ -2 D)5^ -2 E)2^3

This question is from GmatPrep.
x^-1=1/x;
(1/x)^-1=x;
now consider each option (1/5)^-2=5^2=25;
(1/3)^-2=3^2=9;
3^-2=1/9;
5^-2=1/25;
2^3=8;
hence answer should be A
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