pipes and cisterns mcqs to prepare for nts,kppsc,fpsc,ppsc and more | mcqpk.com

pipes and cisterns Mcqs

1. Pipe A can fill a tank in 16 minutes and pipe B cam empty it in 24 minutes. If both the pipes are opened together after how many minutes should pipe B be closed, so that the tank is filled in 30 minutes?
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A. 24

B. 23

C. 20

D. None of these

2. Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?
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A. 25 min

B. 50 min

C. 12 min

D. 15 min

3. Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in?
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A. 4 1/2 hours

B. 1 13/17 hours

C. 2 8/11 hours

D. 3 9/17 hours

4. Two pipes A and B can separately fill a tank in 12 and 15 minutes respectively. A third pipe C can drain off 45 liters of water per minute. If all the pipes are opened, the tank can be filled in 15 minutes. What is the capacity of the tank?
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A. 480 liters

B. 675 liters

C. 600 liters

D. 540 liters

5. Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours. C is closed A and B can fill the remaining par in 7 hours. The number of hours taken by C alone to fill the tank is?
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A. 16

B. 10

C. 14

D. 12

6. 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?
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A. 20 hrs

B. 35 hrs

C. 25 hrs

D. Cannot be determined

7. Pipe A can fill a tank in 5 hours, pipe B in 10 hours and pipe C in 30 hours. If all the pipes are open, in how many hours will the tank be filled?
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A. 3.5

B. 2

C. 3

D. 2.5

8. An outlet pipe can empty 2/3 rd of a cistern in 12 minutes. In 8 minutes, what part of the cistern will be emptied?
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A. 7-Apr

B. 4/9

C. 3-Feb

D. 6-Jan

9. A top can fill a cistern in 8 hours and another can empty it in 16 hours. If both the taps are opened simultaneously the time (in hours) to fill the tank is
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A. 24

B. 8

C. 10

D. 16

10. A tap can fill a tank in 6 hours. After half the tank is filled three more similar taps are opened. What is the total time taken to fill the tank completely?
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A. 4 hrs

B. 3 hrs 45 min

C. 4 hrs 15 min

D. 3 hrs 15 min

11. Two pipes A and B can separately fill a tank in 2 minutes and 15 minutes respectively. Both the pipes are opened together but 4 minutes after the start the pipe A is turned off. How much time will it take to fill the tank?
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A. 10 min

B. 12 min

C. 11 min

D. 9 min

12. pipes P and Q would fill a cistern 18 and 24 minutes respectively. Both pipes being opened, find when the first pipe must be turned off so that the cistern may be just filled in 12 minutes?
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A. after 8 1/2 mins

B. after 9 mins

C. after 12 mins

D. after 10 mins

13. Two pipes A and B together can fill a cistern in 4 hours. Had they been opened separately, then B would have taken 6 hours more than A to fill cistern. How much time will be taken by A to fill the cistern separately?
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A. 2 hrs

B. 6 hrs

C. 8 hrs

D. 1 hr

14. Two pipes function simultaneously the reservoir will be filled in 12 hours. One pipe fills reservoir 10 hours faster than the other. How many hours does the faster pipe take to fill the reservoir?
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A. 25 hrs

B. 28 hrs

C. 35 hrs

D. 20 hrs

15. A large tanker can be filled by two pipes A and B in 60 and 40 minutes respectively. How many minutes will it take to fill the tanker from empty state if B is used for half the time and A and B fill it together for the other half?
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A. 30 min

B. 15 min

C. 20 min

D. 27.5 min

16. A cistern can be filled by a tap in 4 hours while it can be emptied by another tap in 9 hours. If both the taps are opened simultaneously, then after how much time will the cistern get filled?
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A. 4.5 hrs

B. 7.2 hrs

C. 5 hrs

D. 6.5 hrs

17. One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 minutes, then the slower pipe alone will be able to fill the tank in:
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A. 108 min.

B. 192 min.

C. 144 min.

D. 81 min.

18. A cistern has a leak which would empty the cistern in 20 minutes. A tap is turned on which admits 4 liters a minute into the cistern, and it is emptied in 24 minutes. How many liters does the cistern hold?
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A. 720 liters

B. 800 liters

C. 600 liters

D. 480 liters

19. Two pipes A and B can fill a cistern in 12 and 15 minutes respectively. Both are opened together but after 3 minutes A is turned off. After how much more time will the cistern be filled?
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A. 5 1/4 min

B. 9 1/4 min

C. 3 1/4 min

D. 8 1/4 min

20. Two pipes can fill a tank in 18 minutes and 15 minutes. An outlet pipe can empty the tank in 45 minutes. If all the pipes are opened when the tank is empty, then how many minutes will it take to fill the tank?
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A. 10

B. 12

C. 11

D. 13

21. A cistern is normally filled in 8 hours but takes two hours longer to fill because of a leak in its bottom. If the cistern is full, the leak will empty it in?
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A. 40 hrs

B. 20 hrs

C. 25 hrs

D. 16 hrs

22. Two pipes can separately fill a tank in 20 and 30 hours respectively. Both the pipes are opened to fill the tank but when the tank is full, a leak develops in the tank through which one-third of water supplied by both the pipes goes out. What is the total time taken to fill the tank?
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A. 18 hrs

B. 16 hrs

C. 15 hrs

D. 12 hrs

23. 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_________?
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A. 7 hours

B. 7 1/2 hours

C. 6 2/3 hours

D. 6 hours

24. A cistern which could be filled in 9 hours takes one hour more to be filled owing to a leak in its bottom. If the cistern is full in what time will the leak empty it?
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A. 45 hrs

B. 60 hrs

C. 75 hrs

D. 90 hrs

25. A tap can fill a tank in 6 hours. After half the tank is filled, three more similar taps are opened. What is the total time taken to fill the tank completely?
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A. 4 hrs 15 min

B. 4 hrs

C. 3 hrs 45 min

D. 3 hrs 15 min

26. One top can fill a cistern in 2 hours and another can empty the cistern in 3 hours. How long will they take to fill the cistern if both the taps are opened?
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A. 5 Hours

B. 7 Hours

C. 8 Hours

D. 6 Hours

27. A large tanker can be filled by two pipes A and B in 60 minutes and 40 minutes respectively. How many minutes will it take to fill the tanker from empty state if B is used for half the time and A and B fill it together for the other half?
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A. 15 min

B. 20 min

C. 27.5 min

D. 30 min

28. A pipe can fill a cistern in 20 minutes whereas the cistern when fill can be emptied by a leak in 28 minutes. When both pipes are opened, find when the cistern will be full?
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A. 48 min

B. 70 min

C. 60 min

D. 80 min

29. One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill tank in 36 min, then the slower pipe alone will be able to fill the tank in?
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A. 108 min

B. 192 min

C. 81 min

D. 144 min

30. A water tank is two-fifth full. Pipe A can fill a tank in 10 minutes and pipe B can empty it in 6 minutes. If both the pipes are open, how long will it take to empty or fill the tank completely?
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A. 6 min. to empty

B. 9 min. to empty

C. 9 min. to full

D. 6 min. to full

31. 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 is_______?
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A. 6 hrs

B. 6 2/3 hrs

C. 7 1/2 hrs

D. 7 hrs

32. Two taps can separately fill a cistern 10 minutes and 15 minutes respectively and when the waste pipe is open, they can together fill it in 18 minutes. The waste pipe can empty the full cistern in?
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A. 23 min

B. 13 min

C. 7 min

D. 9 min

33. A cistern is normally filled in 8 hours but takes two hours longer to fill because of a leak in its bottom. If the cistern is full the leak will empty it in.
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A. 16 hrs

B. 40 hrs

C. 20 hrs

D. 25 hrs

34. Pipes A and B can fill a cistern in 8 and 24 minutes respectively. They are opened an alternate minutes. Find how many minutes, the cistern shall be full?
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A. 10 min

B. 6 min

C. 12 min

D. 19 min

35. Pipe A can fill a tank in 6 hours. Due to a leak at the bottom, it takes 9 hours for the pipe A to fill the tank. In what time can the leak alone empty the full tank?
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A. 16 hours

B. 15 hours

C. 17 hours

D. 18 hours

36. Two pipes A and B can separately fill a cistern in 60 min and 75 min respectively. There is a third pipe in the bottom of the cistern to empty it. If all the three pipes are simultaneously opened, then the cistern is full in 50 min. In how much time, the third pipe alone can empty the cistern?
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A. 110 min

B. 90 min

C. 100 min

D. 120 min

37. A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is?
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A. 10 hrs

B. 6 hrs

C. 15 hrs

D. 30 hrs

38. A tank is filled in eight hours by three pipes A, B and C. Pipe A is twice as fast as pipe B, and B is twice as fast as C. How much time will pipe B alone take to fill the tank?
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A. 36 hours

B. 32 hours

C. 28 hours

D. 24 hours

39. Two pipes A and B can separately fill a cistern in 10 and 15 minutes respectively. A person opens both the pipes together when the cistern should have been was full he finds the waste pipe open. He then closes the waste pipe and in another 4 minutes the cistern was full. In what time can the waste pipe empty the cistern when fill?
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A. 8 min

B. 10 min

C. 7 min

D. 9 min

40. Two pipes A and B can fill a cistern in 37 1/2 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?
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A. 15 min

B. 9 min

C. 5 min

D. 10 min

41. 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?
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A. 100 gallons

B. 120 gallons

C. 180 gallons

D. 60 gallons

42. A leak in the bottom of a tank can empty the full tank in 6 hours. An inlet pipe fills water at the rate of 4 liters per minute. When the tank is full in inlet is opened and due to the leak the tank is empties in 8 hours. The capacity of the tank is?
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A. 6970 liters

B. 5760 liters

C. 5846 liters

D. 5260 liters

43. Two pipes A and B can fill a tank in 15 min and 20 min respectively. Both the pipes are opened together but after 4 min, pipe A is turned off. What is the total time required to fill the tank?
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A. 10 min 20 sec

B. 12 min 30 sec

C. 14 min 40 sec

D. 11 min 45 sec

44. Two pipes P and Q can fill a cistern in 12 and 15 minutes respectively. Both are opened together, but at the end of 3 minutes the first is turned off. How much longer will the cistern take to fill?
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A. 11 1/4 min

B. 9 1/4 min

C. 7 1/4 min

D. 8 1/2 min

45. Three pipes of same capacity can fill a tank in 8 hours. If there are only two pipes of same capacity, the tank can be filled in___________?
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A. 24 hours

B. 17 hours

C. 16 hours

D. 12 hours

46. A cistern has three pipes, A, B and C. The pipes A and B can fill it in 4 and 5 hours respectively and C can empty it in 2 hours. If the pipes are opened in order at 1, 2 and 3 A.M. When will the cistern be empty?
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A. 7:00 PM

B. 4:00 PM

C. 3:00 PM

D. 5 PM

47. Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?
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A. 11-May

B. 11-Aug

C. 6/11

D. 11-Jul

48. Two pipes A and B can fill a tank in 4 and 5 hours respectively. If they are turned up alternately for one hour each, the time taken to fill the tank is?
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A. 4 hrs 24 min

B. 5 hrs

C. 2 hrs 15 min

D. 3 hrs

49. Two pipes A and B can fill a cistern in 20 and 30 minutes respectively, and a third pipe C can empty it in 40 minutes. How long will it take to fill the cistern if all the three are opened at the same time?
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A. 17 1/7 min

B. 15 1/7 min

C. 19 1/7 min

D. 7 1/7 min

50. A pump can fill a tank with water in 2 hours. Because of a leak, it took 2 1/3 hours to fill the tank. The leak can drain all the water of the tank in?
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A. 4 1/3 hrs

B. 8 hrs

C. 7 hrs

D. 14 hrs

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