Pipes & Cistens

1

Two pipes A and B can fill a cistern in  `37 1/2` minutes and 45 minutes respectively . Both pipes are opened . he cistern will be filled  in just half an  hour , if the pipe B  is turned off after :

A. 5 min.
B. 9 min.
C. 10 min.
D. 15 min.

2

Two pipes can fill a tan in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute.  All he three pipes working together can fill the tan in 15 minutes . The capacity of the tank is :

A. 60 gallons
B. 100 gallons
C. 120 gallons
D. 180 gallons

3

A leak in the bottom of a tank can empty the full tank in 8 hours. An inlet pipe fills water at the rate of 6 litres a minute. When the tank is full , the inlet is opened and  due to he leak, the tank is empty in 12 hours. How many litres does the cistern hold ?

A. 7580
B. 7960
C. 8290
D. 8640

4

A booster pump can be used for filling as well as for emptying a tank. The capacity of he tank is  2400` m^3`. The emptying capacity of the tank is 10`m^3` per minute higher than is filling capacity and the pump needs 8 minutes lesser to empty the tank than it needs to fill it . What is the filling of the pump ?

A. 50`m^3`/min.
B. 60`m^3`/min.
C. 72`m^3`/min.
D. None of these

5

Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are  open for  one hour  each  alternately, the tank  will  be full  in :

A. 6 hrs.
B. `6 2/3`hrs.
C. 7 hrs.
D. `7 1/2`hrs.