Use the three steps to solve the problem. Express the answers using decimals.

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.)

We let

x be the time it took John to get to his uncle's

y be the time it took John to get back from his Uncle's

So,

x + y = 12

And making use of the given velocities

20x = 30y

x = 3/2 y

Substituting to the first equation

3/2 y + y = 12

y = 4.8 h

Substituting to either of the equations

x = 7.2 h