Top 130 Pipe and cistern questions for Competitive Exams [ 100% FREE ]

Introducing an important aspect of the quantitative aptitude section: the Pipe and cistern questions. A common challenge candidates face in various competitive exams, be it banks, SSC, RRB, Insurance and more, is problems related to pipes and cisterns. In this comprehensive article, we delve deep into “Pipe and cistern questions“, ensuring you get the most effective preparation material.

For many, the term “Pipe and cistern questions” can seem daunting, but with the right approach and understanding of the “pipes and cisterns formula“, it becomes manageable. This is why we’re emphasizing on the crucial examples like “two pipes p and q together can fill a cistern” and “two pipes a and b can fill a cistern“. Both these examples will give you a clear perspective on how to approach these problems.

We also recognize the importance of language adaptability in preparation. Therefore, we have also incorporated “pipe and cistern questions in Hindi” and insights on “pipe and cistern in Hindi“. This ensures that you not only understand the crux of the “pipes and cisterns problems” but also can relate to them in a language you’re comfortable with.

Word problems, especially around the “pipes and cisterns formula“, have been a mainstay in competitive exams. While “two pipes p and q together can fill a cistern” or “two pipes a and b can fill a cistern” might seem similar, they can carry nuances that are essential for aspirants to grasp.

Pipes and Cisterns Formula :

Given below are aimportant formulas which shall help you solve the pipes and cistern based questions quicker and more efficiently:

  • If x hours are required to fill up a tank, then part filled in 1 hr =1/x
  • If y hours are required to empty the tank, then part emptied in 1 hour = 1/y
  • If a pipe can fill a tank in x hours and can empty the same tank in y hours. When both the pipes are opened at the same time, then the net part of the tank filled in 1 hr = {(xy) / (y-x)}, provided y>x
  • If a pipe can fill a tank in x hours and can empty the same tank in y hours. When both the pipes are opened at the same time, then the net part of the tank filled in 1 hr = {(xy) / (x-y)}, provided x>y
  • Net work done = (Sum of work done by Inlets) – (Sum of work done by Outlets)
  • One inlet can fill the tank in x hr and the other inlet can fill the same tank in y hrs, if both the inlets are opened at the same time, the time taken to fill the whole tank = {(xy) / (y+x)}
  • If two pipes take x and y hours respectively to fill a tank of water and a third pipe is opened which takes z hours to empty the tank, then the time taken to fill the tank = {1 / (1/x)+(1/y)+(1/z)} and the net part of the tank filled in 1 hr = (1/x)+(1/y)-(1/z)

The syllabus for competitive exams is vast, as we all know. But every topic, including “Pipe and cistern questions“, holds its weight. Therefore, giving due time to understand and practice these “pipes and cisterns problems” is paramount. Especially when considering the intense competition and the challenge to crack these exams.

In conclusion, this article offers an in-depth understanding of “Pipe and cistern questions“, covering essential examples like “two pipes p and q together can fill a cistern” and “two pipes a and b can fill a cistern“, not forgetting the importance of language with “pipe and cistern questions in Hindi” and “pipe and cistern in Hindi“.

Whether you’re just starting out or brushing up your skills, this article is your guide to excel. So, gear up and dive into the world of “Pipe and cistern questions” and ace your upcoming Government sector exams!

Top 130 Pipe and cistern questions for Competitive Exams :

71. There are 15 pipes some are inlets and some are outlets. An inlet pipe can fill the tank in 16 hours and an outlet pipe can empty the tank in 20 hours. If all pipes opened simultaneously, tank is filled in 26 hours 40 minutes. Find the number of outlet pipes.

15 पाइप हैं कुछ भरण हैं और कुछ निकासी हैं। एक भरण पाइप 16 घंटे में टैंक को भर सकता है और एक निकासी पाइप 20 घंटे में टैंक को खाली कर सकता है। यदि सभी पाइप एक साथ खोले गए हैं, तो टैंक 26 घंटे 40 मिनट में भर जाता है। निकासी पाइपों की संख्या को ज्ञात कीजिए।

A. 8
B. 7
C. 10
D. 6
E. None of these

Option “A” is correct.

Let the number of inlet pipes = a

Number of outlet pipes = 15 – a

Let the total capacity of tank = 80 litres

Efficiency of an inlet Pipe = 80/16 = 5 litres/h

Efficiency of an outlet pipe = 80/20 = 4 litres/h

According to question

80/3 x [5 x a –4 x (15 – a)] = 80

5a – 60 + 4a= 3

9a = 63

a = 7

Number of outlet pipes = 15 – 7 = 8

72. The inlet pipe can fill the tank in 16 hours and outlet pipe can empty the same tank in 48 hours. How many additional numbers of outlet pipes is required to be opened to empty the tank in 16 hours?

इनलेट (प्रवेश) पाइप टैंक को 16 घंटे में भर सकता है और आउटलेट (निकास) पाइप उसी टैंक को 48 घंटे में खाली कर सकता है। 16 घंटे में टैंक को खाली करने के लिए कितने अतिरिक्त आउटलेट पाइपों की संख्या को खोलने की आवश्यकता है?

A. 1
B. 3
C. 2
D. 4
E. None of these

Option “C” is correct.

LCM of (16, 48) = 48

Inlet pipe fill the tank in per hour = 3 units

Outlet pipe empty the tank in per hour = 1 unit

Required outlet pipes = 3 – 1 = 2

73. Two inlet pipes can fill a tank in 10 and 12 minutes respectively and an outlet pipe can empty 2 gallons per minute. All the three pipes working together can fill the tank in 6 minutes. What is the capacity of the tank?

दो प्रवेश पाइप क्रमशः 10 और 12 मिनट में एक टैंक को भर सकते हैं और एक निकासी पाइप प्रति मिनट में 2 गैलन खाली कर सकता है। सभी तीनों पाइप एक साथ कार्य करने पर टैंक को 6 मिनट में भर सकते हैं। टैंक की क्षमता क्या है?

A. 60 gallons
B. 120 gallons
C. 180 gallons
D. 240 gallons
E. None of these

Option “B” is correct.

Work done by outlet pipe in 1 hour = 1/6 – (1/10 + 1/12) = -1/60 (negative represents Outlet)

Volume of 1/60 part = 2 gallons

Capacity of full tank = 2 * 60 = 120 gallons

74. An inlet pipe B alone can fill a tank in 10 hours and efficiencies of inlet pipes A and B are respectively 120% and 60% of that of an outlet pipe C. If pipes A and B started together to fill the tank and after 2 hours pipe C is also started, then in what time the tank will be filled?

एक इनलेट पाइप B अकेले एक टैंक को 10 घंटे में भर सकता है और इनलेट पाइप A और B की क्षमता एक आउटलेट पाइप C की क्षमता का क्रमशः 120% और 60% है। यदि पाइप A और B टैंक को भरने के लिए एक साथ खोले जाते हैं और उसके 2 घंटे बाद पाइप C भी खोल दिया जाता है, तो टैंक कितने समय में भर जाएगा?

A. 8 hours
B. 5 hours
C. 6 hours
D. 3 hours
E. 4 hours

Option “B” is correct.

Time taken by B alone to fill the tank = 10 hours

Since efficiency of pipe B is 60% of that of C.

So, time taken by pipe C alone to empty the tank = 10 * (60/100) = 6 hours

Since efficiency of pipe A is 120% of that of C.

So, time taken by pipe A alone to fill the tank = 6 * (100/120) = 5 hours

Let the capacity of tank = LCM of 10, 5 and 6 = 30 units

Part of tank filled by A and B together in 2 hours = 2 * [(30/5) + (30/10)] = 18 units

Remaining part of tank = 30 – 18 = 12 units

Part of tank filled by A, B and C together in 1 hour = [(30/5) + (30/10) – (30/6)] = [6 + 3 – 5] = 4 units

So, time taken by A, B and C together to fill remaining part of tank = 12/4 = 3 hours

Required time = 2 + 3 = 5 hours

75. Pipe A and B are inlet pipes and pipe C is an outlet. Pipe A and B can fill the tank in 6 hours and 7.5 hours respectively and pipe C can empty the tank in 2 hours. If pipes A, B and C together are opened simultaneously, in how many hours the tank is filled/emptied completely?

पाइप A और B इनलेट पाइप हैं और पाइप C एक आउटलेट है। पाइप A और B टैंक को क्रमशः 6 घंटे और 7.5 घंटे में भर सकते हैं और पाइप C टैंक को 2 घंटे में खाली कर सकता है। यदि पाइप A, B और C को एक साथ खोला जाता है, तो कितने घंटे में टैंक पूरी तरह से भर जाता है / खाली हो जाता है?

A. 4
B. 5
C. 6
D. 3
E. None of these

Option “B” is correct.

A = 1/6

B = 1/7.5

C = 1/2

A + B + C = 1/6 + 1/7.5 – 1/2

= (5 + 4 – 15)/30

= -1/5

76. An inlet pipe can fill a tank in 48 minutes and an outlet pipe can empty the same tank in 144 minutes. If both pipes are opened together, then find the time required to fill the 5/12th of the tank?

एक प्रवेश पाइप एक टंकी को 48 मिनट में भर सकता है और एक निकासी पाइप उसी टंकी को 144 मिनट में खाली कर सकता है। यदि दोनों पाइपों को एक साथ खोल दिया जाता है, तो टंकी के 5/12वें हिस्से को भरने में कितना समय लगेगा?

A. 25 hours
B. 20 hours
C. 30 hours
D. 45 hours
E. None of these

Option “C” is correct.

1/48 – 1/144 = (3 – 1)/144 = 2/144 = 1/72

The full tank will be filled in 72 hours

5/12th of the tank will be filled in 5/12 * 72 = 30 hours

77. In three pipes, P and R are inlet pipes and Q is an outlet pipe. If pipes P, Q and R together can fill the tank in 15 hours and pipes P and Q together can fill the tank in 30 hours, then in how many hours R alone fill the tank?

तीन पाइपों में, P और R इनलेट पाइप (भरने की पाइप) हैं और Q एक आउटलेट पाइप (खाली करने की पाइप) है। यदि पाइप P, Q और R एकसाथ टैंक को 15 घंटे में भर सकते हैं और पाइप P और Q एकसाथ टैंक को 30 घंटे में भर सकते हैं, तो R अकेले टैंक को कितने घंटे में भरेगा?

A. 20 hours
B. 45 hours
C. 15 hours
D. 30 hours
E. None of these

Option “D” is correct.

Pipes P, Q and R=1/15

Pipes P and Q=1/30

R=1/15-1/30=1/30

78. Pipe A and Pipe B are inlet pipes and Pipe C is an outlet pipe. Pipe A, B and C together can fill the tank in 200/9 minutes and the ratio of the time taken by Pipe A alone to fill the tank to the time taken by Pipe B and C together to fill the tank is 1:8. Find the time taken by Pipe C alone to empty the tank, if Pipe B takes 15 minutes more than Pipe A to fill the tank.

पाइप A और पाइप B इनलेट पाइप(भरने की पाइप) हैं और पाइप C एक आउटलेट पाइप(खाली करने की पाइप) है। एकसाथ पाइप A, B और C टैंक को 200/9 मिनट में भर सकते हैं और अकेले पाइप A द्वारा टैंक को भरने में लिए गए समय से एकसाथ पाइप B और C द्वारा टैंक को भरने में लिए गए समय का अनुपात 1:8 है। यदि पाइप B टैंक को भरने में पाइप A से 15 मिनट अधिक लेता है, तो अकेले पाइप C द्वारा टैंक को खाली करने में लिया गया समय ज्ञात कीजिए।

A. 50 minutes
B. 45 minutes
C. 40 minutes
D. 30 minutes
E. None of these

Option “A” is correct.

Time taken by Pipe A alone to fill the tank = x minutes

Time taken by Pipe B and C together to fill the tank = 8x minutes

1/x + 1/8x = 9/200

(8 + 1)/8x = 9/200

9/8x = 9/200

x = 25 minutes

Time taken by Pipe B alone to fill the tank = 25 + 15 = 40 minutes

Time taken by Pipe B and C together to fill the tank = 8 * 25 = 200 minutes

1/40 – 1/C = 1/200

1/C = 1/40 – 1/200 = (5 – 1)/200 = 4/200 = 1/50 = 50 minutes

79. Pipes P and Q are inlet pipes and pipe R is an outlet pipe and the ratio of the efficiency of pipes P, Q and R is 2:3:1 respectively. If pipe Q can fill the tank in 16 hours, then in how many hours pipes P, Q and R together can fill half of the tank?

पाइप P और Q इनलेट पाइप(भरने वाली पाइप) हैं और पाइप R एक आउटलेट पाइप(खाली करने वाली पाइप) है और पाइप P, Q और R की दक्षता का अनुपात क्रमशः 2:3:1 है। यदि पाइप Q टैंक को 16 घंटे में भर सकता है, तो एकसाथ पाइप P, Q और R टैंक के आधे हिस्से को कितने घंटे में भर सकते हैं?

A. 6 hours
B. 4 hours
C. 8 hours
D. 12 hours
E. None of these

Option “A” is correct.

Pipe Q can fill the tank = 16 hours

Pipe P can fill the tank = 16 * 3/2 = 24 hours

Pipe R can empty the tank = 16 * 3/1 = 48 hours

Pipes P, Q and R together can fill the whole tank = 1/16 + 1/24 – 1/48 = 3/48 + 2/48 – 1/48 = 4/48 = 1/12 = 12 hours

Therefore, pipes P, Q and R together can fill thehalf of the tank = 12/2 = 6 hours

80. A and B can fill the tank in 4 hrs and 3 hrs respectively and the pipe C empties the tank. If all the pipes are opened simultaneously the tank will be filled in 12 hrs, find the time taken by C to empty the tank.

A और B टंकी को क्रमशः 4 घंटे और 3 घंटे में भर सकते हैं और पाइप C टंकी को खाली कर देता है। यदि सभी पाइपों को एक साथ खोल दिया जाए तो टंकी 12 घंटे में भर जाएगी, C द्वारा टंकी को खाली करने में लिया गया समय ज्ञात कीजिए।

A. 2 hrs
B. 3 hrs
C. 4 hrs
D. 6 hrs
E. 5 hrs

Option “A” is correct.

If C can fills the tank in x hrs,

The work done by A, B and C in one hour,

¼ + 1/3 – 1/x = 1/12

1/x = 7/12 – 1/12

1/x = ½

C can empty the tank in 2 hrs.