Which of the following numbers is not a multiple of 15 ?
(A) 150
(B) 25
(C) 30
(D) 45
(E) 60
We note that $15 \times 10=150,15 \times 2=30,15 \times 3=45$, and $15 \times 4=60$.

Since there is no integer $n$ for which $15 \times n=25$, then 25 is not a multiple of 15 .

ANSWER: (B)