Solve the problem.
-BJ can overhaul a boat's diesel inboard engine in 30 hours. His apprentice takes 60 hours to do the same job. How long would it take them working together assuming no gain or loss in efficiency?
A)12 hr
B)90 hr
C)20 hr
D)8 hr

Question

Quizplus · Accepted Answer

Working together, BJ and his apprentice can complete $\frac{1}{30} + \frac{1}{60} = \frac{1}{20}$ of the job per hour, meaning it would take them 20 hours to complete the job together.

Solve the Problem. -BJ Can Overhaul a Boat's Diesel Inboard Engine in 30