# The leak will make it empty in:

A cistern is normally filled in 8 hours; but takes two hours more to fill because of a leak in its bottom . If the cistern is full, the leak will make it empty in:

- 18 hours
- 28 hours
- 40 hours
- None of these

**Answer: (3) 40 hours **

**Explanation:-**

A cistern is normally filled = 8 hours

Therefore, a cistern can fill in an hour = 1/8

But takes two hours to fill because of a leak in its bottom.

Then, time taken by a cistern to fill = 10 hours

Therefore, a cistern can fill in a an four = 1/10

So, The cistern is empty in an hour by leak = 1/8 – 1/10

= (5 – 4)/40

= 1/40

Thus, the leak will take it empty = 40 hours.

Hence, the correct answer is option (3) 40 hours.