Solve the Problem $\frac { 1 } { 8 }$ Hour Longer

Multiple Choice

Solve the problem.
-In the morning, May drove to an appointment at 50 mph. Her average speed on the return trip in the afternoon was 40 mph. The return trip took $\frac { 1 } { 8 }$ hour longer. How far did she travel to the appointment?

A) 20 mi
B) 7.5 mi
C) 0.5 mi
D) 25 mi