JAMB 2013 · UTME · Q21

If a binary operation $*$ is defined by $x * y = x + 2y$ , find $2 * (3 * 4)$ .

Worked solution (try it first)

Work out the bracket first, doubling the second number: $3 * 4 = 3 + 2 \times 4 = 11$ .
Then $2 * 11 = 2 + 2 \times 11 = 24$ , option C.