GMATPrep: If m and n are integers

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GMATPrep: If m and n are integers

by freshy » Mon Aug 10, 2009 7:54 pm
If m and n are integers, is m odd?

1) n + m is odd
2) n + m = n^2 + 5

OA: B

Would anyone please help explain?

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by tohellandback » Mon Aug 10, 2009 8:13 pm
IMO B
1) n + m is odd
m can be even or odd. Not SUFF

2) n + m = n^2 + 5
n=2,m=7
n=3,m=11.
m is odd in any case.

SUFF
The powers of two are bloody impolite!!

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by ghacker » Mon Aug 10, 2009 9:18 pm
If m and n are integers, is m odd?

1) n + m is odd : If m+n is odd m can be odd or m can be even because we don't know the value of n so this statement is insufficient

2) n + m = n^2 + 5 : We know that n and n^2 have the same parity ; that is if n is even n^2 is even and so on ....
then m = n^2-n +5 but n^2-n is always even so n^2-n+5 is always odd

Hence m is odd

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by freshy » Mon Aug 10, 2009 9:40 pm
Oh, I see, I get it! Thanks!