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 1 of 7.
Sai Shodhan Rao said:
6 years ago
@All.
slower pipe = 3x . 1 part of work = 1/3x.
faster pipe = x. 1 part of work = 1/x.
total time = 36 min 1 part of time = 1/36.
Then, it should be;
total work:
1/x + 1/3x = 1/36.
4/3x = 1/36.
x = 48 mins.
And the slower pipe 3x = 3(48) = 144 mins.
slower pipe = 3x . 1 part of work = 1/3x.
faster pipe = x. 1 part of work = 1/x.
total time = 36 min 1 part of time = 1/36.
Then, it should be;
total work:
1/x + 1/3x = 1/36.
4/3x = 1/36.
x = 48 mins.
And the slower pipe 3x = 3(48) = 144 mins.
(10)
Rishabh said:
8 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)
Alan S said:
2 years ago
@All.
Here's an easy way:
Let the time for slower pipe be = x
Then the faster pipe will be = 3x
The ratio between both pipes is = 1 : 3
When we add 1 and 3 (1+3), we get 4.
Now simply, just multiply 4 by 36.
The answer is 144 min.
Hence, Option C is correct.
Here's an easy way:
Let the time for slower pipe be = x
Then the faster pipe will be = 3x
The ratio between both pipes is = 1 : 3
When we add 1 and 3 (1+3), we get 4.
Now simply, just multiply 4 by 36.
The answer is 144 min.
Hence, Option C is correct.
(6)
Xavier said:
3 years ago
Faster x min slower 3x min eff 3:1 total work LCM of x, 3x is 3x ,
Slower+ faster together = 3x/4.
Given slower + faster together can fill in = 36.
=> 3x/4 = 36.
=> x= 144/3.
Slower pipe =3x =3*144/3= 144.
Slower+ faster together = 3x/4.
Given slower + faster together can fill in = 36.
=> 3x/4 = 36.
=> x= 144/3.
Slower pipe =3x =3*144/3= 144.
(6)
Ssrao said:
6 years ago
Sslower pipe = 3x
Faster pipe = x
1/x + 1/3x = 1/36
(3+1)/3x = 1/36
1/x = 1/27.
Then,
Faster pipe takes 27 mins.
Slower pipe takes 27*3 = 81 mins.
Why this is wrong? Explain.
Faster pipe = x
1/x + 1/3x = 1/36
(3+1)/3x = 1/36
1/x = 1/27.
Then,
Faster pipe takes 27 mins.
Slower pipe takes 27*3 = 81 mins.
Why this is wrong? Explain.
(5)
Lommin said:
5 years ago
What does 1/x or 1/ A or 1/B mean here? Please explain me.
(2)
Samyuktha Sriram said:
2 years ago
Let V be the volume of the tank, the pipes are filling.
If x and x/3 mins are the time taken by pipe 1 and pipe 2, then V/x and V*3/x are the volumes filled by each of the pipes per minute.
So,
V/x + V*3/x = V/36.
Here, V/36 is the volume that is filled in the tank per minute by both pipes together. V gets cancelled and that is how we get the expression,
1/x + 3/x = 1/36.
While proceeding to solve this, we obtain 144 as the answer.
If x and x/3 mins are the time taken by pipe 1 and pipe 2, then V/x and V*3/x are the volumes filled by each of the pipes per minute.
So,
V/x + V*3/x = V/36.
Here, V/36 is the volume that is filled in the tank per minute by both pipes together. V gets cancelled and that is how we get the expression,
1/x + 3/x = 1/36.
While proceeding to solve this, we obtain 144 as the answer.
(2)
Dhilber said:
8 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:
8 years ago
Why can't we take 3x for faster one instead of x/3 for faster one?
(1)
YOGI M said:
10 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)
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