Data Sufficiency

AbeNeedsAnswers wrote:If n is an integer, is n + 1 odd?

(1) n + 2 is an even integer.
(2) n -1 is an odd integer.

We need to determine whether n + 1 is odd. The only way n + 1 will be odd is if n is even; therefore, we need to determine whether n is even.

Statement One Alone:

n + 2 is an even integer.

Statement one tells us that n is an even integer (since 2 more than an even integer is also an even integer). Because n is an even integer, we know that n + 1 is odd. Statement one is sufficient to answer the question.

Statement Two Alone:

n - 1 is an odd integer.

Since subtraction rules for even and odd integers are the same as addition rules for even and odd integers, we know that if n - 1 is odd, then n itself must be even, and hence n + 1 must also be odd. Statement two is sufficient to answer the question.

Answer: D