A and B can do a certain work in 6 hours, and A, B and C together take 4 hours to do the same. How long will it take for C alone to accomplish the task?

12 hours 4 hours 2 hours 6 hours

12 hours

A + B = 6 hrs A + B + C =4 hrs ⇒ Efficiency ⇒  A+B+C = 3 , A+B = 2, therefore C = 1. Hence, time taken by C to complete the work alone = \(\frac{12}{1}\) = 12 hours.