Question

Two pipes can separately fill a cistern in 5h and 6h respectively and a third pipe can empty it in 10h. How long would it take to fill the cistern if all the pipes were used together? *​

Answer 1

Step-by-step explanation:

Given:

Time taken by first pipe = 2 hours

Time taken by second pipe = 3 hours

Concept:

If a pipe fill “x” parts of the cistern in 1 hour,

Then the time taken to fill complete cistern would be “1/x” hours.

Calculation:

According to the question,

Part of the tank filled by both pipes in 1 hour:

⇒ (1/2) + (1/3)

⇒ (3 + 2)/6

⇒ 5/6 parts

As per the concept,

The required time taken by both pipes to fill the complete cistern will be 6/5 hours.

1 hour = 60 minutes.

⇒ 6/5 hours = 6/5 × 60 = 72 minutes.

⇒ 72 minutes = 1 hour 12 minutes.

∴ The time taken by both pipes to fill complete cistern is 1 hour 12 minutes.