Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 6)
6.
Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:
Answer: Option
Explanation:
| Work done by the waste pipe in 1 minute = | 1 | - |  |
1 | + | 1 |  |
| 15 | 20 | 24 |
| = | |
1 | - | 11 | |
| 15 | 120 |
| = - | 1 | . [-ve sign means emptying] |
| 40 |
 Volume of |
1 | part = 3 gallons. |
| 40 |
Volume of whole = (3 x 40) gallons = 120 gallons.
Discussion:
48 comments Page 3 of 5.
Siddhesh said:
8 years ago
The part of tank filled in 1 min by all pipes=(1/20)+(1/24)-(1/x).
= (44x-480)/480x.
The time required to fill 1 tank.
= 480x/(44x-480) minutes.
Where, x = time in minutes required to empty the tank by the waste pipe.
But all pipes fill the total tank in 15 minutes.
So, 15 = 480x/(44x-480).
x = 40 minutes.
The capacity of tank = discharge per minute * time.
= 3 * 40,
= 120 gallons.
= (44x-480)/480x.
The time required to fill 1 tank.
= 480x/(44x-480) minutes.
Where, x = time in minutes required to empty the tank by the waste pipe.
But all pipes fill the total tank in 15 minutes.
So, 15 = 480x/(44x-480).
x = 40 minutes.
The capacity of tank = discharge per minute * time.
= 3 * 40,
= 120 gallons.
Md.gohor rizvi. said:
9 years ago
Let the capacity of the tank or pump X gallons.
The first pipe can fill the tank in 20 min.
The second pipe can fill the tank in 24 min.
1st pipe 20 min. fill X gallon. So, First pipe in one min can fill X/20 gallons.
So, the second pipe can fill in X/24 gallons.
And the third pipe flows out 3 gallons per minute.
So, X/20 + X/24 - 3 equal X/15 therefore X equal 120 gallons.
The first pipe can fill the tank in 20 min.
The second pipe can fill the tank in 24 min.
1st pipe 20 min. fill X gallon. So, First pipe in one min can fill X/20 gallons.
So, the second pipe can fill in X/24 gallons.
And the third pipe flows out 3 gallons per minute.
So, X/20 + X/24 - 3 equal X/15 therefore X equal 120 gallons.
Aqueeb Khan said:
9 years ago
How can we solve this problem by the unitary method?
Nasir said:
9 years ago
Let, the capacity of the tank is x gallon.
3 pipes 1 min can fill up (1 / 20 +1 / 24 - 3),
So, 15 min can fill up, 15 (1 / 20 + 1 / 24 - 3),
We get 15 (1 / 20 + 1 / 24 - 3) equally to x.
We get the calculation of x is 120 gallons.
3 pipes 1 min can fill up (1 / 20 +1 / 24 - 3),
So, 15 min can fill up, 15 (1 / 20 + 1 / 24 - 3),
We get 15 (1 / 20 + 1 / 24 - 3) equally to x.
We get the calculation of x is 120 gallons.
(1)
ASHUTOSH SAHANI said:
9 years ago
120 gallon is waste water, which drains out from the tank in 15 min.
S.n.raju said:
9 years ago
Given,
First pipe takes 20h.
Second pipe take 24h.
ALL together take 15h.
Assuming that capacity of tank L. C. M [20, 24, 15] = 120.
First pipe can fill 6u/m.
Second pipe fill 5u/m.
All three fill 8u/m -------> 1.
First and second together fill in 11m/u----------> 2.
From 1 and 2 we get;
Third pipe fills the tank in 3u/m that is 120/3 = 40u of total fill.
But given 3 gallons are empty.
3 * 40 = 120gallons (capacity of tank).
First pipe takes 20h.
Second pipe take 24h.
ALL together take 15h.
Assuming that capacity of tank L. C. M [20, 24, 15] = 120.
First pipe can fill 6u/m.
Second pipe fill 5u/m.
All three fill 8u/m -------> 1.
First and second together fill in 11m/u----------> 2.
From 1 and 2 we get;
Third pipe fills the tank in 3u/m that is 120/3 = 40u of total fill.
But given 3 gallons are empty.
3 * 40 = 120gallons (capacity of tank).
Sindhu said:
9 years ago
Why making the values in the ratio one we get.
C = 1/15 - (1/20 + 1/24).
C = 1/15 - (1/20 + 1/24).
Nitin said:
9 years ago
L.C.M of 20, 15, 24 = 120 unit total capacity.
120/3 = 40.
40 * 3 = 120.
120/3 = 40.
40 * 3 = 120.
Snhk said:
9 years ago
L.C.M of 20, 15, 24 = 120 unit total capacity.
1st pipe = 6 unit.
2nd pipe = 5 unit.
= 11 unit.
Total 120/15 = 8 unit.
3rd (-) pipe capacity = (11 - 8) = 3 unit.
As UTC 120.
3rd pipe can empty = 120/3 = 40 unit which is = 3 gallons per minute.
Hence the capacity of the tank (40*3) =120 gallons.
1st pipe = 6 unit.
2nd pipe = 5 unit.
= 11 unit.
Total 120/15 = 8 unit.
3rd (-) pipe capacity = (11 - 8) = 3 unit.
As UTC 120.
3rd pipe can empty = 120/3 = 40 unit which is = 3 gallons per minute.
Hence the capacity of the tank (40*3) =120 gallons.
Sreeram said:
9 years ago
A and B.
Time: 20min and 24min.
Efficiency: 6 and 5.
Work done A+B in 1 min = 11.
Work done A+B in 15 min = 11*15 = 165.
Tank emptied by C in 15 min = 45.
= 165 - 45 = 120 gallons.
Time: 20min and 24min.
Efficiency: 6 and 5.
Work done A+B in 1 min = 11.
Work done A+B in 15 min = 11*15 = 165.
Tank emptied by C in 15 min = 45.
= 165 - 45 = 120 gallons.
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