how to set up this probelm

Question

zIt takes John 2 hours to ride his bike to the beach. At the beach, his friend Bill said he would drive him home. They loaded up John’s bike and it took them half an hour to get back to John’s house. If Bill drives 30 mph faster than John rides his bike, how fast does John ride his bike?

Answer 1

 

 R*2 = 1/2*(R+30)

 

 2R = 1/2*R + 15

 

 4R = R+30

 

3R = 30

 

R=10