AHSME 1968 Problem 25

Ace runs with constant speed and Flash runs $x$ times as fast, $x>1$. Flash gives Ace a head start of $y$ yards, and, at a given signal, they start off in the same direction. Then the number of yards Flash must run to catch Ace is: $\text{(A) } xy \text{(B) } \frac{y}{x+y} \text{(C) } \frac{xy}{x-1} \text{(D) } \frac{x+y}{x+1} \text{(E) } \frac{x+y}{x-1}$