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 2 of 7.
Rishabh said:
7 years ago
So as per ques.(simple trick).
Pipe A (slower)complete its work to 1unit/min.
Then Pipe B (faster)complete its work to 3unit/min.
Then total unit in 1 min=4units/min.
Then total units in total time=4*36=144units.
NOW B(Slower pipe) time=(1min/1unit)x144units = 144units.
Pipe A (slower)complete its work to 1unit/min.
Then Pipe B (faster)complete its work to 3unit/min.
Then total unit in 1 min=4units/min.
Then total units in total time=4*36=144units.
NOW B(Slower pipe) time=(1min/1unit)x144units = 144units.
(9)
Dhilber said:
7 years ago
Let take x is the time taken by a faster pipe and 3x be the time taken by the slowest pipe.
hence 3x+x=36,
x=9.
which means in total 36 min.
9 min taken by fastest pipe and remaining 27 min taken by the slowest pipe.
So instead of using the fastest pipe, we use the slowest pipe then it takes 3 times more time than the slowest pipe.
Hence, 9*3=27.
So total time taken will be 27+27=54.
Please correct me, if I am wrong.
hence 3x+x=36,
x=9.
which means in total 36 min.
9 min taken by fastest pipe and remaining 27 min taken by the slowest pipe.
So instead of using the fastest pipe, we use the slowest pipe then it takes 3 times more time than the slowest pipe.
Hence, 9*3=27.
So total time taken will be 27+27=54.
Please correct me, if I am wrong.
(2)
Akhil galla said:
7 years ago
Why can't we take 3x for faster one instead of x/3 for faster one?
(1)
Akshatha N said:
8 years ago
Why cannot we take faster pipe=3x, instead of x/3?
Pranathi said:
8 years ago
Thank you @Reshma.
Khagendra said:
8 years ago
Most effective solution, Thanks @Laxman.
Jayaprakash said:
8 years ago
Great @Indrajit.
Pavan said:
8 years ago
Actually A=3B because A pipe fill d tank 3 times fast as B pipe.
So A=3B but in time.
Then B = A/3
Let, A= x-----(1) assume i.e B=x/3---------(2)
Formula 1/A+1/B=1/36 substitute both in
1/x+1/x/3 = 1/36,
1/x+3/x = 1/36,
4/x = 1/36.
=>x=4*36 =>144.
So A=3B but in time.
Then B = A/3
Let, A= x-----(1) assume i.e B=x/3---------(2)
Formula 1/A+1/B=1/36 substitute both in
1/x+1/x/3 = 1/36,
1/x+3/x = 1/36,
4/x = 1/36.
=>x=4*36 =>144.
YOGI M said:
9 years ago
P1 = 3P2 According to the question.
[P1 + P2] = 1/36.
[P2] = ?
P1 + P2 = 1/36.
3P2 + P2 = 1/36.
4P2 = 1/36.
P2 = 1/144 {1/36 * 4 = 144}.
==>P2 = 144min.
[P1 + P2] = 1/36.
[P2] = ?
P1 + P2 = 1/36.
3P2 + P2 = 1/36.
4P2 = 1/36.
P2 = 1/144 {1/36 * 4 = 144}.
==>P2 = 144min.
(1)
Shan said:
10 years ago
I am getting a different answer,
Two pipe fills the tank in 36 min.
Let's take slower one = A.
Faster one as B.
So, B = A*3.
If B+A = 36.
Then B = 27 and A = 9.
If B alone has to fill the tank then it will fill in.
27min (of B) + 9/3 of A = 27+3 = 30 min.
And if go like this and A alone has to fill the tank then it would be:
30*3 = 90 min.
Why I this is not right someone Please explain?
Two pipe fills the tank in 36 min.
Let's take slower one = A.
Faster one as B.
So, B = A*3.
If B+A = 36.
Then B = 27 and A = 9.
If B alone has to fill the tank then it will fill in.
27min (of B) + 9/3 of A = 27+3 = 30 min.
And if go like this and A alone has to fill the tank then it would be:
30*3 = 90 min.
Why I this is not right someone Please explain?
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