If a and n are integers

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If a and n are integers

by himu » Sun Feb 10, 2013 9:10 pm
If a and n are integers and n > 1, is n odd?
(1) a^(n-1) > a^n

(2) a^n > a^(3n)

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by GMATGuruNY » Mon Feb 11, 2013 5:31 am
himu wrote:If a and n are integers and n > 1, is n odd?
(1) a^(n-1) > a^n

(2) a^n > a^(3n)
Since n>1, each statement indicates the following:
(integer a)^(smaller positive power) > (integer a)^(bigger positive power).
This relationship is valid only if a<0 and the exponent on the lefthand side is EVEN (so that the lefthand side becomes positive), while the exponent on the righthand side is ODD (so that the righthand side stays negative).
In each statement, for the exponent on the righthand side to be ODD, n itself must be odd.
Thus, each statement on its own is sufficient.

The correct answer is D.
Last edited by GMATGuruNY on Mon Jul 13, 2015 10:47 am, edited 1 time in total.
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by himu » Mon Feb 11, 2013 7:59 pm
Thanks GMATGuruNY, that is the correct ans :)