Question

If N is an even integer, then which of the following must be an odd integer.

(A) N
(B)-N+1
(C) 3N
(D) 3N+3

Answer 1

B and D

Explanation:

Let n=2k, where k is an integer.

(A) 2k, which is even

(B) -2k+1=2(-k+1)-1, which is odd

(C) 3(2k)=6k, which is even

(D) 3(2k)+3=6k+3=2(3k+1)+1, which is odd