Pipes and cistern problems are asked in many competitive
examinations including SSC, IBPS etc. solving these problems requires more time
if the candidate does not know the shortcut method to solve this type of
problem. It is more important to clear basic concept in these problems. So here
is a shortcut method to solve pipes and cistern problems with basic concept.

Below are

**pipes and cisterns problems shortcut**with easy concept. The below given 2 problems with solution will let you understand the pipes and cistern concept easily.
Suppose you are given a problem like the one given below.

Two pipes can fill a tank in 10 hours and 15 hours
respectively while a third pipe can empty the tank in 20 hours. If all the three
pipes are made to operate simultaneously, determine how much time is required
to fill the tank?
The shortcut method to solve this type of pipes and cisterns
problems is that you have to put them in ratio to 1 and add the values of pipes
which are filling the tank and subtract the value which is emptying the tank. The
process is shown below.

Tank will be filled in 1 hours= (1/10)+(1/15)-(1/20)= (6+4-3)/60

(LCM of 10,15,20 is 60 by shortcut method)

Tank filled in 1 hour = 7/60

So full tank will be filled in =60/7 hours Ans.

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For SHORTCUT TRICKS OF ALL QUANTITATIVE APTITUDE INCLUDING TIME AND WORK, TIME AND DISTANCE, PROFIT AND LOSS ETC., CLICK ON TRICKS TAB ON NAVIGATION BAR GIVEN ON TOP OF SITE

The above question clears the basic concept of pipes and
cistern. The basic point is you have to add the pipe’s value filling the tank
and subtract the pipe’s value emptying it.

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Now let us take another example.

Two pipes A and B can fill a cistern in 36 hours and 45
hours respectively and a third pipe C can empty it in 30 hours. Both A and B
pipes are kept opened for 7 hours and then third pipe C is also opened. Determine
the time required to fill the tank.

Solution: now in this question,

Tank filled by 2 pipes filling together in 7 hour=
7[(1/36)+(1/45)]= 7/20

Remaining part= 1-(7/20)= 13/20

Tank filled by all the 3 pipes together in 1 hour= (1/36)+(1/45)-(1/30)=
1/60

Now all 3 pipes working together can fill 1/60 tank in 1
hour.

So 13/20 tank will be filled in = (13/20)*60= 39 hours

Total time to fill the full tank= 39+7= 46 hours Ans.