Working alone, Wade can paint a certain room in 7 hours. Rhonda can paint the same room in 5 hours.

Question

How long will it take them working together to paint the room? Give a rational expression to solve the problem, then solve the problem. Round your answer to the nearest hundredth if necessary.

Answer 1

Wade can do 1/7 of the job in an hour

Rhonda can do 1/5 of the job in an hour

Together they can do 1/7 + 1/5 = 5//35 + 7/35 = 12/35 of the job in an hour

12/35 job 1 job

------------ = ---------

1 hour x hours

x = 35/12 = 2.92 hours