A pipe can fill an empty tank in 11 hours, while another pipe can empty the…
2026
A pipe can fill an empty tank in 11 hours, while another pipe can empty the filled tank in 44 hours. If both pipes are opened simultaneously when the tank is empty, how many hours will it take for the tank to be three-fourths full?
- A.
11
- B.
22
- C.
33
- D.
44
Attempted by 13 students.
Show answer & explanation
Correct answer: A
Step 1: Calculate the 1-hour efficiency of both pipes.
Filling pipe efficiency = 1/11 per hour.
Emptying pipe efficiency = 1/44 per hour.
Step 2: Calculate the net efficiency when both are open.
Net efficiency = (1/11) - (1/44)
= (4/44) - (1/44) = 3/44 per hour.
Step 3: Calculate the time taken to fill three-fourths (3/4) of the tank.
Required work = 3/4.
Time = Required work / Net efficiency
= (3/4) / (3/44)
= (3/4) * (44/3) = 11 hours.
Final Answer: Option 1