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Is the positive integer n odd?

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Source: — Data Sufficiency |

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by Brent@GMATPrepNow » Mon Sep 18, 2017 5:35 am
ardz24 wrote:Is the positive integer n odd?

(1) n= 2k+1, where K is positive integer
(2) 2n+1 is an odd integer

OA: B

I confused why the answer is B instead of D?
What's the source of this question?
I ask because the correct answer to this question is neither B nor D.
The correct answer is A

(1) If n= 2k+1 (where k is positive integer) then n is definitely odd. In fact, this is the actual definition of an odd integer.

(2) If n = 4, then 2n + 1 = (2)(4) + 1 = 9 (and odd number). In this case, n is EVEN
If n = 3, then 2n + 1 = (2)(3) + 1 = 7 (and odd number). In this case, n is ODD
So, statement 2 is NOT sufficient.

Answer: A

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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