A can complete a task in 15 hours, B in 10 hours, and C in 5 hours. If they all work together, how l

A. 2 hours

B. 3 hours

C. 4 hours

D. 5 hours

E. None of the above

Answer: B. 3 hours

Their combined work rate is 1/15 + 1/10 + 1/5 = 1/3. Therefore, they will complete the task in 3 hours.

Posted in: Time & Work - Aptitude - Mathematics