Solve the Problem by Using a System of Equations

Solve the problem by using a system of equations.
-Two cars leave from a city at the same time and travel in the same direction. One car travels one-third and one-third times as fast as the other. After 5 hr, they are 300 mi apart. What are the speeds of the cars?

A) Slower car: 40 mph; faster car: 100 mph
B) Slower car: 50 mph; faster car: 110 mph
C) Slower car: 45 mph; faster car: 105 mph
D) Slower car: 35 mph; faster car: 95 mph