# Tips And Tricks And Shortcuts Of Pipes & Cisterns Questions

## Tips and Tricks for Pipes and Cisterns

Inlet pipe is the pipe for filling the Cistern while Outlet Pipe is for emptying the cistern.Suppose a  pipe can fill a tank in x hours, Then, the pipe can fill same tank in 1 hour = $\frac{1}{n}$ parts . Let us look at some of the Tips And Tricks for Pipes and Cisterns that are given below.

### Pipes and Cisterns Tips and Tricks & Shortcuts

• Here, are quick and easy tips and tricks for you to solve Pipes and Cisterns questions quickly, easily, and efficiently in competitive exams.

### Tips and tricks and shortcuts of  Pipes and Cisterns questions

• Pipes and Cisterns questions on are almost like Time and Work questions.
• In pipes and cistern problems, the portion of the tank are filled or emptied is calculated and it is relatively same as the amount of work done in time and work problems.
• Similarly, time taken to fill or empty a tank completely or to a desired level is the time taken to do a piece of work.

### Type 1: Calculate time taken to fill a tank by two or more pipes

Question 1. Two pipes A and B are connected to a container. Pipe A can empty the container in 20 minutes and pipe B can empty the container in 30 minutes. Both A and B are opened together. Find out the time to empty the container completely?

Options:

A. 12 mins

B. 14 mins

C. 10 mins

D. 7 mins

Solution:    Let the size of the container be = 60 units [LCM (20, 30)]

Efficiency of pipe A = $\frac{60}{20}$ = 3 units

Efficiency of pipe B =$\frac{60}{30}$ = 2 units

Combined efficiency of pipe A and pipe B = 5 units/min

So, time required to empty the container with both pipes = $\frac{60}{5}$= 12 mins

Correct option: A

### Type 2 : Tips and Tricks and Shortcuts for Pipes and Cisterns Problems related to Calculate time taken to fill a tank having a hole or leakage

Question 1. A pipe takes 5 hours to fill a water tank but because of leakage, it takes 3 hours more. Find out the number of hours taken by leakage pipe to empty the full water tank?

Options:

A. $\frac{40}{3}$ hrs

B. $\frac{3}{40}$ hrs

C. $\frac{3}{47}$ hrs

D. $\frac{2}{51}$ hrs

Solution:    Water tank filled in 5 hours = $\frac{1}{5}$

Now, due to outlet pipe, 1 hour part filled = $\frac{1}{8}$

Part of the water tank emptied in 1 hour = $\frac{1}{5}$$\frac{1}{8}$ = $\frac{3}{40}$

So, the leak will empty the full water tank in $\frac{40}{3}$ hrs

Correct option: A

### Type 3: Calculate Time Taken When Pipes Are Opened For Different Periods

Question 1: There are three pipes A, B and C, which can fill the tank in 10 hours. All the three pipes were opened for together for 5 hours, C is closed and inlets A and B fill the remaining part in 12 hours. Find the time taken by C alone to fill the tank.

Options:

A. 18 hrs 7 mins

B. 17 hrs 8 mins

C. 18 hrs

D. 17 hrs

Solution:     Part of the tank filled by the pipes A, B and C in 1 hour = $\frac{1}{10}$

Part of the tank filled by the pipes A, B and C in 5 hours = 5 * $\frac{1}{10}$ = $\frac{5}{10}$= $\frac{1}{2}$

Remaining portion of tank to be filled = 1 – $\frac{1}{2}$ = $\frac{1}{2}$

Now, when A and B are open

Part of the tank filled by A and B in 1 hour =$\frac{ 1 x \frac{1}{2}}{ 12}$= $\frac{1}{24}$

Therefore, part of the tank filled by C in 1 hour = $\frac{1}{10}– \frac{1}{24}$ = $\frac{7}{120}$

Time taken by C alone = $\frac{1}{ \frac{7}{120}}$ = $\frac{120}{7}$ hours which can be written as 17 hrs 8 mins

Correct option: B

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### 5 comments on “Tips And Tricks And Shortcuts Of Pipes & Cisterns Questions”

• Sonam Choubey

Similarly type 2
Option correct option should be A not B

• Sonam Choubey

Do correction
Type 1

Solution is correct but
You mentioned wrong option

It should be option A is 12
Becuase option B is wrong and value is 14

• HelpPrepInsta

We resolved your issue. Hope you are doing Great.!!!
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