Pipe and Cistern (Railway Maths) (Part – I)

Total Questions: 50

11. 28 pipes are connected to a tank. Some of them pour water into the tank, whereas the rest drain water out of it. Each of the pipes that fill water can fill the empty tank in 14 hours, whereas any of the drainpipes can empty the filled tank in 35 hours, If all the pipes are opened simultaneously when the tank is empty and the tank is filled in 2.5 hours, how many of pipes were drain pipes ? [NTPC CBT - I 19/03/2021 (Morning) ]

Correct Answer: (a) 16
Solution:

12. Two pipes can fill a tank in 20 hours and 60 hours respectively. A third pipe is an outlet pipe. If all three are opened together, the tank gets filled up in 40 hours. What time will the outlet pipe take to empty the full tank? [RRB JE 29/05/2019 (Afternoon)]

Correct Answer: (a) 24 hours
Solution:

13. A pipe P can drain out water from a tank in 20 hours. Another pipe Q can drain 20 litres per hour. If both drains are opened, the tank is emptied in 12 hours. What is the capacity of the tank? [RRB JE 02/06/2019 (Afternoon)]

Correct Answer: (d) 600 litres
Solution:

14. A tank is fitted with three inlets. The first two when opened simultaneously fill the tank in the same time as that taken by the third inlet alone. The second inlet can fill the tank 5 hours faster than the first and 4 hours slower than the third. In how many hours can the first inlet alone fill the tank? [RRB JE 26/06/2019 (Morning)]

Correct Answer: (a) 15 hours
Solution:

15. Pipes A and B, when working together, can fill an empty tank in 8 hours. If B is stopped after 2 hours, it will take a total of 11 hours to fill the tank. How long would it take A to fill the empty tank alone? [RRB ALP Tier-I 14/08/2018 (Evening)]

Correct Answer: (b) 12 hours
Solution:

16. One of the two inlet pipes works twice as efficiently as the other. The two, working alongside a drain pipe that can empty a cistern all by itself in 8 hours, can fill the empty cistern in 8 hours. How many hours will the less efficient inlet pipe take to fill the empty cistern by itself ? [RRB ALP Tier - I 17/08/2018 (Afternoon) ]

Correct Answer: (c) 12
Solution:

17. Two pipes A and B can fill an empty cistern in 32 and 48 hours, respectively. Pipe C can drain the entire cistern in 64 hours when no other pipe is in operation. Initially, when the cistern was empty Pipe A and Pipe C were turned on. After a few hours, Pipe A was turned off and Pipe B was turned on instantly. In all it took 112 hours to fill the cistern. For how many hours was Pipe B turned on ? [RRB ALP Tier - I 29/08/2018 (Afternoon) ]

Correct Answer: (d) 72
Solution:

18. Two pipes namely A,B can fill a sump in 25 minutes and half an hour respectively and a pipe C 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: [RRB ALP Tier - I 30/08/2018 (Morning) ]

Correct Answer: (c) 450 gallons
Solution:

19. Pipe A is 3 times faster than pipe B. Both pipes together fill a tank in 36 min. How much time will pipe A alone take to fill the tank ? [Group D 25/08/2022 (Morning) ]

Correct Answer: (d) 48 min
Solution:

20. Two pipes A and B can fill the tank in 5 hours and 8 hours respectively. Pipe C can empty the same tank in 10 hours. Find the time taken to fill the empty tank when all the pipes are opened simultaneously. [Group D 25/08/2022 (Evening) ]

Correct Answer: (b)
Solution: