Question

Pipes P and Q can fill a tank in 20 and 16 hours respectively. Pipe Q alone was opened for 1/4 of time and later P also was opened. In how many hours was the tank filled?

Answer 1

Answer:

Explanation: Let the required time be x hours, then Pipes & Citern

⇒ x/16+3x/80 = 1⇒ x= 11=10 hours.

Step-by-step explanation: