SSC CHSL 2022 PYQ — Question 72

The correct answer is Option 1 i.e 60 hrs

Given:

Pipe A can fill the tank in 15 hours

Due to a leak, it is filled in 20 hours.

Formula Used:

Total Work = Efficiency × total time

Explanation:

Let the total work be done by pipe A and a leak be LCM (15, 20) = 60 units

Now, efficiency of pipe A to fill the tank ($60 \over 15$) = 4 units/hour

Efficiency of pipe A and the leak in bottom together ($60 \over 20$) = 3 units/hour

So the efficincy of the leak in the bottom to empty the tank (4 - 3) = 1 unit/hour

So, the time taken by the leak to empty the tank alone ($60 \over 1$) = 60 hours

Hence the required answer is 60 hours.