Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 7)
7.
A tank is filled in 5 hours by three pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank?
Answer: Option
Explanation:
Suppose pipe A alone takes x hours to fill the tank.
| Then, pipes B and C will take | x | and | x | hours respectively to fill the tank. |
| 2 | 4 |
 |
1 | + | 2 | + | 4 | = | 1 |
| x | x | x | 5 |
 |
7 | = | 1 |
| x | 5 |
x = 35 hrs.
Discussion:
33 comments Page 3 of 4.
Naveencool said:
9 years ago
Take A as x = 1, B = 2, C = 4.
The total is 7, each contribution is in 5 hours. Then 7 * 5 = 35 hours.
The total is 7, each contribution is in 5 hours. Then 7 * 5 = 35 hours.
(1)
YOGI M said:
9 years ago
[A + B + C] = 1/5.
According to question;
C = 2B = 4A----------- 2(2A )= 4A.
B = 2A.
[A] = ?
A + B + C = 1/5.
A + 2A + 4A = 1/5,
7A = 1/5,
A = 1/7 * 5,
A = 1/35 ==> 35hr.
According to question;
C = 2B = 4A----------- 2(2A )= 4A.
B = 2A.
[A] = ?
A + B + C = 1/5.
A + 2A + 4A = 1/5,
7A = 1/5,
A = 1/7 * 5,
A = 1/35 ==> 35hr.
(1)
Savita said:
9 years ago
1/5 is taken wrt to 1 hr but not A B C they are taken as A, 2A, 4A which has to to be taken wrt 1hr but in equation how are they equating A, 2A,4A to 1/5 in an equation. if we want to solve an equation it should be write to 1 hr only.
Bhagyasree said:
8 years ago
@Savitha.
We know that capability of A, B, C.
More capability takes less time to complete the work. it means that strengths is inversely proportional to time.
A + 2A + 4A inversely to x/5(x is some constant)
X = 5*7A .......35A.
35A part work done in......1 hour.
A's total work.................?
So, ? =35hrs.
We know that capability of A, B, C.
More capability takes less time to complete the work. it means that strengths is inversely proportional to time.
A + 2A + 4A inversely to x/5(x is some constant)
X = 5*7A .......35A.
35A part work done in......1 hour.
A's total work.................?
So, ? =35hrs.
Manikandan said:
8 years ago
Here how that 1/5 comes?
R. Gowtham Raj said:
7 years ago
Here, it should be x + x/2 + x/4.
Sagen said:
7 years ago
@Manikandan.
A+B+C together fill the tank in 5 hrs. In 1 hr they together fill ta tank par 1/5 of the tank.
A+B+C together fill the tank in 5 hrs. In 1 hr they together fill ta tank par 1/5 of the tank.
Vineeth said:
7 years ago
Considering the value of A as X, B as 2X and C as 4X. Can anybody help me in solving this ?
(2)
Ritwik said:
6 years ago
B is twice as fast as A so if A=x, B=2x then how x/2?
(3)
Nikhil said:
5 years ago
The pipe C is twice as fast as B.
Means ratio of C:B = 2:1.
B is twice as fast as A.
Means B:A = 2:1.
Combine ratio of A:B:C = 1:2:4.
NOW,
The tank is filled in 5 hours by A,B,C.
so the addition of ratio =7(total parts of the tank)
So, 7*5 =35 hours to fill.
Now we have to find A's time.
A's ratio is 1. So divide 35by 1 =35 is the answer.
Means ratio of C:B = 2:1.
B is twice as fast as A.
Means B:A = 2:1.
Combine ratio of A:B:C = 1:2:4.
NOW,
The tank is filled in 5 hours by A,B,C.
so the addition of ratio =7(total parts of the tank)
So, 7*5 =35 hours to fill.
Now we have to find A's time.
A's ratio is 1. So divide 35by 1 =35 is the answer.
(8)
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