Question

It took John 12 hours riding his bike to make the round trip to his uncle's. If he averaged 20 mph out and 30 mph back, how long did he travel each way? (Round answer to nearest tenth.)

Answer 1

d=distance traveled one way
t=d/s
d/20 + d/30 = 12
3d+2d=60(20)
5d=720
d=720/5 = 144 mi one way
144/20 = 7.2 hrs at 20 mph
144/30 = 4.8 hrs at 30 mph