Pipes and Cisterns – Concept, Formulas, Tricks, and Questions
Pipes and Cisterns is a common topic in quantitative aptitude for exams like SSC, Bank PO, Railway, CAT, and campus placements.
These problems are similar to Time and Work problems, but instead of workers completing a job, pipes fill or empty a tank.
Understanding the work rate concept makes these questions very easy to solve.
In this guide, you will learn:
- Pipes and Cisterns concept
- Important formulas
- Quick tricks
- Solved examples
- Practice questions
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Pipes and Cisterns Online Test |
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| Pipes & Cisterns Quiz 1 | Pipes & Cisterns Quiz 2 | Pipes & Cisterns Quiz 3(Inactive) |
Related Aptitude Topics
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- Time and Work Questions
- Problems on Ages
- Averages Aptitude Questions
- Ratio and Proportion Questions
- Profit and Loss Questions
- Percentage Questions
This creates a strong aptitude topic cluster.
What Are Pipes and Cisterns Problems?
Pipes and Cisterns problems deal with filling or emptying a tank using pipes.
There are two types of pipes:
Inlet Pipe
An inlet pipe fills the tank with water.
Outlet Pipe
An outlet pipe empties the tank.
If both pipes operate together, we calculate the net filling rate.
Important Pipes and Cisterns Formula
Given below are a few important formulas that will help you handle pipes and cistern-related concerns faster and more efficiently:
Tips to Solve Pipes and Cisterns Questions Faster
Follow these exam tips:
- Convert time into work rate
- Use LCM shortcut method
- Remember outlet pipes have negative work rate
- Practice previous exam questions
- Avoid complex fractions
With practice, most pipes and cisterns problems can be solved in under 30 seconds.
Sample Questions: Pipes and Cisterns
Q1. A Pipe can fill a tank in 2N hours. After one-fourth tank is filled, four more similar pipes are opened in the tank, find total time required to fill the tank completely?
- 0.8N
- 0.5N
- 0.6N
- 0.7N
- 0.9N
Solution:
Q2. 14 pipes working seven hours a day can empty a completely filled oil tank in 15 days. If ‘X’ such pipes working ten hours a day can empty the same oil tanks in 7 days?
- 22
- 20
- 21
- 23
- 24
Solution:
Q3. Pipe A and B alone can fill a tank in ‘x’ hours and ‘x+10’ hours respectively. If both pipes together fill the tank in 12 hours, then the time taken by B alone to fill the tank is what percent of that of A alone?
- None of these
- 175%
- 125%
- 200%
- 150%
Solution:
Q4. Three pumps A, B and C are opened to fill a tank such that B and C can fill the tank alone 18 hours and 12 hours respectively. Pipe A can empty it 15 hours After 5 hours pipe A is closed. Then how many hours the remaining tank will be filled?
- None of these
- 2 hours 50 min.
- 1 hours 45 min.
- 1 hours 15 min.
- 4hours 36 min.
Solution:
Q5. one pipe fills a water tank three times faster than another pipe. If the two pipes together can fill the empty tank in 36 min, then how much time will the slower pipe alone take to fill the tank?
- 2h 24min
- 2h
- 1h 21min
- 1h 48min
- None of these
Solution:
Q6. Two pipes A and B can fill a tank in 40 hrs and 50 hrs respectively while a third pipe C can empty the tank in 60 hrs. If all the pipes are opened together for 20 hrs and then pipe C is closed then in what time the tank can be filled?
- 800/27 hours
- 400/27 hours
- 600/27 hours
- 1600/27 hours
- None of these
Solution:
Q7. Pipe P and Q fill the tank in 8 hr and 10 hr respectively and pipe R can empty it in 20 hrs. If all the pipes are open simultaneously find how much time they will take to fill the tank 50%.
- 16/7 hours
- 20/7 hours
- 19/7 hours
- 15/7hours
- None of these
Solution:
Q8. Two pipes A and B can fill the tank in 40 and 60 minutes respectively. Both the pipes are opened together, after how many minutes should the pipe B be turned off, so that the tank be fill in 30 minutes?
a. 15 min
b. 20 min
c. 25 min
d. 28 min
e. None of these
Solution:
The questions above will help you understand how to answer Pipes and Cistern questions, as well as the kind of questions that may be asked about this topic.
Pipes and Cisterns is an important topic in quantitative aptitude. By understanding the work rate concept, formulas, and shortcuts, you can solve even difficult problems quickly.
Regular practice and proper understanding of concepts will help you perform well in SSC, Bank, Railway, and other competitive exams.