Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 11)
11.
One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 minutes, then the slower pipe alone will be able to fill the tank in:
Answer: Option
Explanation:
Let the slower pipe alone fill the tank in x minutes.
| Then, faster pipe will fill it in | x | minutes. |
| 3 |
 |
1 | + | 3 | = | 1 |
| x | x | 36 |
 |
4 | = | 1 |
| x | 36 |
x = 144 min.
Discussion:
67 comments Page 5 of 7.
Poornima said:
1 decade ago
Why do we need to take time as 1/time?
Bhushan said:
1 decade ago
Above ans is right. Thing this way.....we want to find the time that the slower pipe alone can fill the tank not the time from total 36mins hence we take 1/A+1/b=1/36 so that we are finding the time from 100% and not from 36 mins. We are basically generalizing by taking the numerator as 1.
Rishab said:
1 decade ago
How do we know that 1/a + 1/b = 1/36 ?
Shanti lal dhaker said:
1 decade ago
We may also solve in this manner i.e.
x + x/3 =36
=>
4x/3 = 36
or =>
x=27
x + x/3 =36
=>
4x/3 = 36
or =>
x=27
Sonu choudhary said:
1 decade ago
I am still not understand why we take 1/x+3/x=1/36. Please reply.
Manasa said:
1 decade ago
Thanks RESHMA.
Anusha said:
1 decade ago
its simple ya , one pipe =1/x;
anther pipe =3/x:
=4x36 sec=144.
comment pls.
anther pipe =3/x:
=4x36 sec=144.
comment pls.
Miss Mathphobia said:
1 decade ago
Why not x+x/3=36?
It gives me answer as 27...
It gives me answer as 27...
Karthiga said:
1 decade ago
Why we take 1/x+3/x instead of x + x/3 =36 ?
Reshma said:
1 decade ago
@Pranathi.
We are discussing about d time. If we take the time taken by slower pipe as x and faster time pipe as 3x. It means that faster pipe takes more time. Which means our assumption is wrong.
We are discussing about d time. If we take the time taken by slower pipe as x and faster time pipe as 3x. It means that faster pipe takes more time. Which means our assumption is wrong.
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