If j and k are integers, and 2j + k = 15, which of the following must be true?

[BTGModeratorVI]

[spoiler]If j and k are integers, and 2j + k = 15, which of the following must be true?[/spoiler]

A. j + k is odd.
B. j + k is even.
C. j is odd.
D. k is odd.
E. k > j

Answer: D
Source: Kaplan

[Brent@GMATPrepNow]

[spoiler]If j and k are integers, and 2j + k = 15, which of the following must be true?[/spoiler]

A. j + k is odd.
B. j + k is even.
C. j is odd.
D. k is odd.
E. k > j

Answer: D
Source: Kaplan

15 is ODD
2j is EVEN for all integer values of j

So, 2j + k = 15 becomes: (some EVEN number) + k = ODD
So, it must be the case that k is ODD

Answer: D

Cheers,
Brent