# Pipe P and Q can fill a cistern in 14 hr and 16 hrs respectively. But

A. 110 hours

B. 111 hours

C. 112 hours

D. 113 hours

### Right Answer is: C

#### SOLUTION

Let total capacity of water = 112 units

Efficiency of P = 8

Efficiency of Q = 7

Net efficiency = 8+ 7 = 15

Time Taken by pipe P and Q to fill the cistern = = 7 hours and 28 minutes

But due to leakage in cistern, Pipe P and Q take 32 min more to fill the cistern

Total time taken with leakage = 7 hours and 28 minutes + 32 minutes = 8 hrs

Now we have to understand that work done by leakage in 8 hour is equal to work done by pipe P and Q in 32 min.

So, cistern filled by pipe P and Q in 32 minutes = units

So time taken by leakage to empty 8 units = 8 hours

time taken by leakage to empty 112 units = 112 hours

Pipe P and Q can fill a cistern in 14 hr and 16 hrs respectively. But