Question

An inlet pipe takes 8 hours to fill a tank. An outlet pipe takes 12 hours to empty it. If both pipes are opened simultaneously, in how many hours will the tank be filled?
1. 36 
2. 8
3. 24
4. 12

Answer 1

Correct Answer - Option 3 : 24

Given:

An inlet pipe takes 8 hours to fill a tank. An outlet pipe takes 12 hours to empty.

Calculation:

 ⇒ Time is taken to fill in 1 hour = 1/8

 ⇒ Time taken to empty in 1 hour =  -1/12

 ⇒ If both pipes are opened simultaneously tank be filled in 1 hour = 1/8 – 1/12 = 1/24 hours

∴ The total time taken is 24 hours.