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 :

11. A and B together can fill a tank in 12 mins, B and C together can fill the tank in 15 mins and C and A can fill a tank in 20 mins. In how much time will B take to fill the tank ?

A और B मिलकर एक टैंक को 12 मिनट में भर सकते हैं, B और C मिलकर टैंक को 15 मिनट में भर सकते हैं और C और A टैंक को 20 मिनट में भर सकते हैं। B को टैंक भरने में कितना समय लगेगा?


Option “C” is correct.

Given:

Time taken by A + B = 12 mins

Time taken by B + C = 15 mins

Time taken by C + A = 20 mins

Formula  used:

Total work = Efficiency × Number of days

Calculation:

L.C.M of (12, 15 and 20) = 60 = Total work

⇒ Efficiency of  (A + B) = 60/12 = 5 units

⇒ Efficiency of (B + C) = 60/15 = 4 units

⇒ Efficiency of (C + A) =60/20 = 3 units

⇒ Total eff. 2(A + B + C) = 12 unit

⇒ (A + B + C) = 6 unit 

⇒ Efficiency of B = Efficiency of (A + B + C) – Efficiency of (A + C)

⇒ Efficiency of C = 6 – 3 = 3 units

⇒ Time taken by B to fill the tank = 60/3

⇒ 20 mins

∴ B will take 20 mins to fill the tank

12. Pipes A and B can fill a tank in 6 hours and 9 respectively and pipe C can empty the full tank in 12 hours. If all three pipes are opened together when a tank is empty, in how many hours will 35% tank be filled?

पाइप A और B क्रमशः 6 घंटे और 9 में एक टैंक भर सकते हैं और पाइप C 12 घंटे में पूरा टैंक खाली कर सकता है। यदि टैंक खाली होने पर तीनों पाइप एक साथ खोले जाते हैं, तो 35% टैंक कितने घंटे में भरेगा?


Option “D” is correct.

Shortcut Trick

Let the capacity of tank be 36 units

The efficiency of A = 6 unit per hr

The efficiency of B = 4 unit per hr

Efficiency of C = -3 unit per hr

35% of tank capacity = 36 × 35/100 = 12.6

Combined efficiency = 6 + 4 – 3 = 7

∴ Required time = 12.6 ÷ 7 = 1.8 h

13. Two inlet pipe A and B fill a tank in 2 hour and 3 hour respectively. While an outlet C empty the same tank in 4 hour. If all the three pipe open together then in what time they fill the tank ? 

दो भरने वाले पाइप A और B क्रमशः 2 घंटे और 3 घंटे में एक टैंक भरते हैं। जबकि एक खाली करने वाला पाइप C सामान टैंक को 4 घंटे में खाली करता है। यदि तीनों पाइप एक साथ खुले हैं तो वे कितने समय में टैंक को भरते हैं?


Option “A” is correct.

Efficiency of pipe A = 1/2

Efficiency of pipe B = 1/3

Efficiency of pipe C = 1/4

Efficiency of pipe A, B and C when they open together = 1/2 + 1/3 – 1/4 = (6 + 4 – 3)/12 = 7/12

∴ Time taken by pipe A, B and C to fill the tank when they open together = 12/7 hour

14. Pipes A and B can fill a tank in 16 hours and 24 hours, respectively, and pipe C alone can empty the full tank in x hours. All the pipes were opened together at 10:30 AM, but C was closed at 2:30 PM. If the tank was full at 8:30 PM on the same day, then what is the value of x?

नल A और B एक टंकी को क्रमशः 16 घंटों और 24 घंटों में भर सकते हैं, और नल C अकेले भरी हुई टंकी को x घंटों में खाली कर सकता है। सभी नलों को एकसाथ पूर्वाह्न 10:30 बजे खोला जाता है, लेकिन C को अपराह्न 2:30 बजे बंद कर दिया जाता है। यदि टंकी समान दिन अपराह्न 8:30 भर जाती है, तो x का मान क्या ?


Option “A” is correct.

Pipes A and B can fill a tank in 16 hrs and 24 hrs respectively, and pipe C alone can empty the full tank in x hrs.

Pipe A and pipe B work for = 10 : 30 AM to 8 : 30 PM = 10 hrs

Pipe C work for = 10 : 30 to 2 : 30 PM = 4 hrs

According to the question

(10) × (1/16 + 1/24) – (4/x) = 1

⇒ (10) × [(3 + 2)/48] – (4/x) = 1

⇒ (10) × (5/48) – (4/x) = 1

⇒ (25/24) – (4/x) = 1

⇒ 4/x = (25/24) – 1

⇒ 4/x = 1/24

⇒ x = 24 × 4 = 96 hr

Short trick:

Total work = 48

Efficiency ratio of A to B = 3 : 2

Let the efficiency of pipe C be k, then

Pipe A and pipe B work for = 10:30 AM to 8:30 PM = 10 hrs

Pipe C work for = 10:30 to 2:30 PM = 4 hrs

According to the question

10(3 + 2) – 4k = 48

⇒ 10 × 5 – 4k = 48

⇒ 4k = 50 – 48

⇒ k = 1/2

So, pipe C alone can empty the full tank in = 48/(1/2) = 96 hr

So, x = 96 hrs

15. Pipes A and B are filling pipes while pipe C is an emptying pipe. A and B can fill a tank in 72 and 90 minutes respectively. When all the three pipes are opened together, the tank gets filled in 2 hours. A and B are opened together for 12 minutes, then closed and C is opened. The tank will be empty after:

पाइप A और पाइप B भरने वाले जबकि पाइप C एक खाली करने वाला पाइप है। A और B क्रमशः 72 और 90 मिनट में एक टैंक को भर सकते हैं। जब तीनों पाइप एक साथ खोले जाते हैं, तो यह टैंक 2 घंटे में भर जाता है। A और B को 12 मिनट के लिए एक साथ खोला जाता है, फिर बंद कर किया जाता है और C को खोला दिया जाता है। यह टैंक कितने समय में खाली हो जाएगा?


Option “A” is correct.

2 hr = 120 minutes

Total work = 360

Let efficiency of C be x, then

5 + 4 + x = 3

⇒ x = 9 – 3

⇒ x = -6

Work done by pipe A and B in 12 minutes = (5 + 4) × 12 = 108

The tank empty by pipe C in = 108/6 = 18 minutes

16. Pipe A can completely fill an empty tank in 11 hours. Pipe B can empty the same completely filled tank in 15 hours. If they are opened together, in how much time the empty tank will get filled?

पाइप A पूरी तरह से 11 घंटे में एक खाली टैंक भर सकता है। पाइप B 15 घंटे में पूरी तरह से भरे टैंक को खाली कर सकता है। यदि उन्हें एक साथ खोला जाता है, तो खाली टैंक कितने समय में भर जाएगा?


Option “C” is correct.

Pipe A (Fill) = 11 hours

Pipe B (Empty) = 15 hours

⇒ L.C.M. of 11 and 15 is 165

⇒ Let the total work be 165 units

⇒ Efficiency of pipe A = 165/11 = 15 units

⇒ Efficiency of pipe B = 165/15 = – 11 units ((Empty))

⇒ Pipe A and B can fill the tank = 165/(15 – 11) = 165/4 = 41.25 hours

⇒ Pipe A and B can fill the tank = 41 hours 15 minutes

∴ The tank will be filled by pipe A and pipe B in 41 hours 15 minutes.

17. Two pipes A and B can fill the tank in 5 hours and 4 hours respectively while another pipe C can empty the tank in 8 hours. If for the first 2 hours pipe A and C are connected and after that, all the pipes are connected together, then approximately in how much time (in minutes) the remaining tank will be filled?

दो पाइप A और B एक टंकी को क्रमशः 5 घंटे और 4 घंटे में भर सकते हैं जबकि एक अन्य पाइप C टंकी को 8 घंटे में खाली कर सकता है। यदि पहले 2 घंटे के लिए पाइप A और C को जोड़ा जाता है और उसके बाद, सभी पाइप को एक साथ जोड़ दिया जाता है, तो टंकी का शेष भाग लगभग कितने समय (मिनट में) भर जाएगा?


Option “A” is correct.

Pipes A and B can fill the tank in 5 hours and 4 hours respectively

Pipe C can empty the tank in 8 hours

Let the total quantity of tank be LCM of (5, 4 and 8) = 40 units

Quantity of tank filled by A in 1 hour = 40/5 = 8 units

Quantity of tank filled by B in 1 hour = 40/4 = 10 units

Quantity of tank emptied by C in 1 hour = 40/8 = 5 units

According to the question,

For the first 2 hours pipe, A and C is connected

⇒ Quantity of tank filled in first 2 hours = 2 × (8 – 5) = 6 units

⇒ Remaining quantity = 40 – 6 = 34 units

If all the pipes are connected together then the quantity of tank filled in 1 hour = 8 + 10 – 5 = 13 units

∴ Time taken to fill the remaining quantity = 34/13 = 2 (8/13) hours

⇒2 (8/13)×60=156.9≈157minutes

18. One pipe can fill an empty cistern in 7.8 hours while another can drain the cistern when full in 19.5 hours. Both the pipes were turned on when the cistern was half-empty. How long will it take for the cistern to be full?

एक पाइप 7.8 घंटे में एक खाली टंकी भर सकता है जबकि दूसरा पाइप 19.5 घंटों में भरी हुई टंकी को खाली कर सकता है। जब टंकी आधी-खाली होती है तब दोनों पाइप चालू किए जाते है। पूरा भरने में कितना समय लगेगा?


Option “C” is correct.

One pipe can fill a cistern in = 7.8 hours = 78/10 = 39/5 hours

∴ In 1 hour one pipe can fill = 5/39

Another pipe can drain the cistern in = 19.5 hours = 195/10 = 39/2 hours

∴ In 1 hour another pipe can drain = 2/39

∴ In 1 hour they together can fill = 5/39 – 2/39 = 3/39

Let, they can fill a half-empty cistern in x hours

According to the question,

⇒ 3x/39 = 1/2

⇒ x = 39/6 = 6.5

∴ They together can fill a half-empty cistern in 6.5 hours

19. Two inlet pipes A and B can fill an empty cistern in 22 and 33 hours respectively. They start work together but pipe A had to be closed 5.5 hours before the cistern was full. How many hour in all did it take the two pipes to fill the cistern?

दो प्रवेशिका पाइप A और B एक खाली टंकी को क्रमशः 22 और 33 घंटे में भर सकती है। वे मिलकर काम करना प्रारंभ करते हैं लेकिन पाइप A को टंकी को भरने से 5.5 घंटा पहले बंद किया जाना था। तो दोनों पाइपों द्वारा टंकी को भरने के लिए कितना समय लिया गया था?


Option “B” is correct.

Two inlet pipes A and B can fill an empty cistern in 22 and 33 hours respectively.

Suppose capacity of the tank = 66 units (LCM of 22 and 33)

Hence,

Efficiency of pipe A = 66/22 = 3 units

Efficiency of pipe B = 66/33 = 2 units

They start work together but pipe A had to be closed 5.5 hours before the cistern was full.

Suppose the tank got full in x hours;

So,

3 × (x – 5.5) + 2 × x = 66

⇒ 3x – 16.5 + 2x = 66

⇒ 5x = 82.5

⇒ x = 16.5

Hence, it takes 16.5 hours to fill the cistern by the two pipes.

20. Two pipes A and B can fill a tank in 12 minutes and 15 minutes, respectively. When an outlet pipe C is also opened, then the three pipes together can fill the tank in 10 minutes. In how many minutes can C alone empty the full tank?

दो पाइप A और B क्रमशः 12 मिनट और 15 मिनट में एक टैंक भर सकते हैं। जब एक निकासी पाइप C भी खोल दिया जाता है, तो तीनों पाइप एक साथ टैंक को 10 मिनट में भर सकते हैं। C अकेले कितने मिनट में पूरा टैंक खाली कर सकता है?


Option “B” is correct.

GIVEN:

Time taken by pipe A to fill the tank = 12 minutes 

Time taken by pipe B to fill the tank = 15 minutes

Total time taken = 10 minutes

FORMULAE USED:

Total Time taken = 1/(1/A + 1/B – 1/C)

CALCULATION:

10 = 1/(1/12 + 1/15 – 1/C)

(1/12 + 1/15 – 1/C) = 1/10 

1/C = 3/20 – 1/10

1/C = 1/20

C = 20 minutes

ALTERNATE METHOD

 L.C.M of 12, 15 and 10 = 60 = Total work

Efficiency of pipe A = 60/12 =5 units/minute

Efficiency of pipe B = 60/15 = 4 units/minute

Efficiency of pipe (A + B + C) = 60/10 = 6 units/minute

Efficiency of pipe C = 6 – (5 + 4) units/minute

Efficiency of pipe C = -3 units/minute

Here negative sign means tank is emptying

So, Time taken by pipe C to empty the tank = 60/3 minutes

⇒ 20 minutes

∴ Time taken by pipe C to empty the tank is 20 minutes

Click here to Practice Previous year 10000+ Questions of Quantitative Aptitude
Click here to Practice Get Free E-books and notes of All Subjects 

Pages: 1 2 3 4 5 6 7 8 9 10 11 12