Question

14. Two pipes can fill a tank in 6 hours and 8 hours respectively. A third pipe can empty the same tank in 12 hours. If all the pipes start working together, how long it will take to fill
the tank?
None of these
4.8 Hrs
9 Hrs
10 Hrs​

Answer 1

The time taken by the first pipe to fill the tank = 6 hours.

Therefore, work done by the first pipe in one hour = 1/6

The time taken by the second pipe to fill the tank = 8 hours.

Therefore, work done by the second pipe in one hour = 1/8

The time taken by the third pipe to empty the tank = 12 hours.

Therefore, work done by the third pipe in one hour = 1/12

Therefore, work done by all the pipes in one hour together

= (1/6+1/8-1/12)

= 5/24

Therefore, time taken by all the pipes = 24/5 hours = 4.8 hours

So, the answer will be 4.8 hours.