Introduction : Pipes and cisterns

SAMPLE PROBLEMS

1. A tank is filled in 5 hours by three pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank?

a. 20 hours
b. 25 hours
c. 35 hours
d. Cannot be determined
e. None

2. Two pipes can fill a tank in 6 hours and 8 hours respectively while a third pipe empties the full tank in 12 hours. If all the three pipes operate simultaneously, in how much time will the tank be filled?

a. 7(1/2) hrs
b. 4(4/5) hrs
c. 3(2/7) hrs
d. 1(1/5) hrs

3. A booster pump can be used to fill as to empty the tank. The capacity of the tank is 1200 m³. The emptying capacity of the tank is 10 m³ per minute higher than its filling capacity and the pump requires 4 minutes lesser to vacant the tank than it requires to fill it. Calculate the filling capacity of the pump.

a. 25
b. 50
c. 75
d. 100

4. It is observed that the pipe A can fill the tank in 15 hrs and the same tank is filled by pipe B in 20 hrs. The third pipe C can vacant the tank in 25 hrs. If all the pipes get opened initially and after 10 hrs, the pipe C is closed, then how long will it take to fill the tank?

a. 3 hrs
b. 7 hrs
c. 12 hrs
d. 20 hrs

5. If two pipes function simultaneously, the reservoir will be filled in 24 hrs. One pipe fills the reservoir 20 hours faster than the other. How many hours does it take for the second pipe to fill the reservoir?

a. 12 hrs
b. 30 hrs
c. 44 hrs
d. 60 hrs

Answers—  1.C   2.B  3.B    4.C   5.D