If y varies directly as x and y = 8 when x = 4, what is the value of y when x = 16?

Direct variation means y = kx for a constant k. Since y = 8 when x = 4, k = 8 ÷ 4 = 2; when x = 16, y = 2 × 16 = 32, so the answer is 32.

AI-written and checked against the verified answer.