The average of 1,3 and $x$ is 3 . What is the value of $x$ ?
(A) 4
(B) 5
(C) 2
(D) 3
(E) 1
Since the average of three numbers equals 3 , then their sum is $3 \times 3=9$.

Therefore, $1+3+x=9$ and so $x=9-4=5$.

ANSWER: (B)