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Home › Grade8 › OLYMPIAD › Math Olympiad-Grade-8 › Pipes & Cisterns › Pipes & Cisterns Worksheet-3

Pipes & Cisterns Worksheet-3

Pipes & Cisterns Worksheet-3

 

  1. Two pipes A and B can fill a cistern in 12 minutes and 15 minutes respectively while a third pipe C can empty the full tank in 6 minutes. A and B are kept open for 5 minutes in the beginning and then C is also opened. In what time is the cistern emptied?

(a) 30 min         (b) 33 min         (c) min     (d) 45 min

 

  1. Two pipes A and B can fill a tank in 6 hours and 4 hours respectively. If they are opened on alternate hours and if pipe A is opened first, in how many hours, the tank shall be full?

(a) 4                    (b)                 (c) 5                    (d)

 

  1. 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) hrs         (c) 7                    (d) hrs

 

  1. A booster pump can be used for filling as well as for emptying a tank. The capacity of the tank is 2400 m3. The emptying capacity of the tank is 10 m3 per minute higher than its filling capacity and the pump needs 8 minutes lesser to empty the tank than it needs to fill it. What is the filling capacity of the pump?

(a) 50 m3/min                               (b) 60 m3/min

(c) 72 m3/min                               (d) None of these

 

  1. 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 the leak, the tank is empty in 12 hours. How many litres does the cistern hold?

(a) 7580             (b) 7960             (c) 8290             (d) 8640

 

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

(a) 60 gallons                                (b) 100 gallons

(c) 120 gallons                              (d) 180 gallons

 

  1. Two pipes A and B can fill a cistern in minutes and 45 minutes respectively. Both pipes are opened. The 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

 

  1. Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is:

(a) 10                  (b) 12                  (c) 14                  (d) 16

 

Answer Key:

(1)-d; (2)-c; (3)-c; (4)-a; (5)-d; (6)-c; (7)-b; (8)-c