Question

A cistern is normally filled in 6 hrs but takes 4 hrs longer to fill because of a leak in its bottom. If the cistern is full, the leak will empty it in how much time?



options



1



16 hrs



2



20 hrs



3



15 hrs



4



none of these

Answer 1

Answer:

15 hours

Step-by-step explanation:

The cistern normally get filled in 6 hours.

But due to leakage it takes 6+4 = 10 hours.

Lets take LCM of 6 and 10 = 30, ie 30 parts of the cistern is to be filled.

So it normally fills 30/6 = 5 parts of the cistern in an hour.

Due to leakage, it fills only 30/10 = 3 parts in an hour.

From this we can say that, the leakage reduces 5 - 3 = 2 parts in an hour.

So the leak will empty the cistern in 30/2 = 15 hours.