GMAT prep DS question

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GMAT prep DS question

by mlane25269 » Sat Jul 19, 2008 1:41 pm
Can someone explain? Thanks!
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Re: GMAT prep DS question

by parallel_chase » Sat Jul 19, 2008 2:22 pm
mlane25269 wrote:Can someone explain? Thanks!
Is n an odd number

Statement I

n=2k+1

Anything multiplied by 2 will yield an even integer. Therefore, n will always be odd in this case. Always remember the rules of odd and even

even+even = even
odd+even = odd

Sufficient.


Statement II

2n + 1 is odd

In this case n could be odd as well as even. The above condition will always result in an odd integer irrespective of weather n is odd or even.

Not Sufficient.

Hence A is the answer.