Two cars leave Phoenix and travel in the same direction. One car travels 4/3
times as fast as the other.
After 6 hours they are 90 miles apart. What are the rates of the cars?
speed of slower car --- x mph
speed of faster car ---- (4/3)x
they both went for 6 hours
6(4/3)x - 6x = 90
8x - 6x = 90
2x = 90
x = 45 mph
slower car: 45 mph
faster car: 60 mph