Pipes A and B can fill a tank in 16 hours and 24 hours, respectively, whereas pipe C and empty the full tank is 40 hours. All three pipes are opened together, but pipe C is closed after 10 hours. After how many hours will the remaining part of the tank be filled?

Answer: Option A

Solution

Answer: Option A

Solution:

All three pipe opened together in 10 hours = (15 + 10 - 6) × 10 = 190
Remaining work = 240 - 190 = 50
Remaining work done by A and B $$=\frac{50}{15+10}=2$$