Question

Let * be a binary operation on $Z$. If $a^* b=2 a b$ where $a, b \in Z$ then the value of $19 * 16$ is

(A) 608

(B) 70

(C) 68

(D) 304

Answer 1

SOLUTION :  We have $a * b=2 a b ; a, b \in Z$

$\therefore 19 * 16=2(19)(16)=608 \text {. }$

Above Correct Answer is Option A.