On a 240 kilometre trip, Corey's father drove $\frac{1}{2}$ of the distance. His mother drove $\frac{3}{8}$ of the total distance and Corey drove the remaining distance. How many kilometres did Corey drive?
(A) 80
(B) 40
(C) 210
(D) 30
(E) 55
On a 240 kilometre trip, Corey's father drove $\frac{1}{2}$ of the distance. His mother drove $\frac{3}{8}$ of the total distance and Corey drove the remaining distance. How many kilometres did Corey drive?
(A) 80
(B) 40
(C) 210
(D) 30
(E) 55

## Solution

If Corey's father and mother drove $\frac{1}{2}$ and $\frac{3}{8}$ the total distance, respectively, altogether they drove $\frac{1}{2}+\frac{3}{8}$ or $\frac{7}{8}$ th the total distance. Thus Corey must have driven $\frac{1}{8} \times 240$ or 30 kilometres.