Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 14)
14.
Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full in:
Answer: Option
Explanation:
| (A + B)'s 1 hour's work = |  |
1 | + | 1 |  |
= | 9 | = | 3 | . |
| 12 | 15 | 60 | 20 |
| (A + C)'s hour's work = | |
1 | + | 1 | |
= | 8 | = | 2 | . |
| 12 | 20 | 60 | 15 |
| Part filled in 2 hrs = | |
3 | + | 2 | |
= | 17 | . |
| 20 | 15 | 60 |
| Part filled in 6 hrs = | |
3 x | 17 | |
= | 17 | . |
| 60 | 20 |
| Remaining part = | |
1 - | 17 | |
= | 3 | . |
| 20 | 20 |
| Now, it is the turn of A and B and | 3 | part is filled by A and B in 1 hour. |
| 20 |
Total time taken to fill the tank = (6 + 1) hrs = 7 hrs.
Discussion:
52 comments Page 5 of 6.
Salman pasha said:
7 years ago
It is coming as 6 hours.
Manisha said:
7 years ago
Thanks @Roshni.
(1)
Pankajkumarnaik9@gmail.com said:
6 years ago
Thanks for the answer @Piyush.
(2)
Xx1884 said:
5 years ago
A-12,B-15,C-20 TOTAAL FACTOR IS 60,
A+B+C 1 HOUR WORK IS 5,
SO B one hour work is 15/5=3, C=20/5=4.
Here one thing mentioned A is working all time so we do not take that value so A+B =4+3=7 HOURS.
A+B+C 1 HOUR WORK IS 5,
SO B one hour work is 15/5=3, C=20/5=4.
Here one thing mentioned A is working all time so we do not take that value so A+B =4+3=7 HOURS.
(3)
Govind said:
5 years ago
See......LCM of 12,15,20 is 60.
Therefore Total Tank Capacity is 60.
The individual capacity of A in One hour is 60/12=5.
The individual capacity of B in One hour is 60/15=4.
The individual capacity of C in One hour is 60/20=3.
A+B=5+4=9 in one hour.
A+C=5+3=8 in one Hour.
in two hours 17 liter. 17*3=51 liter in 6 hour and turns is A+B=9 in one Hour means.
6+1=7 Hour Final Answer.
Therefore Total Tank Capacity is 60.
The individual capacity of A in One hour is 60/12=5.
The individual capacity of B in One hour is 60/15=4.
The individual capacity of C in One hour is 60/20=3.
A+B=5+4=9 in one hour.
A+C=5+3=8 in one Hour.
in two hours 17 liter. 17*3=51 liter in 6 hour and turns is A+B=9 in one Hour means.
6+1=7 Hour Final Answer.
(27)
Saisam said:
5 years ago
Suppose it takes "x" time for the complete tank to fill,so now tap"A" runs for all the time that is A*x whereas B and C runs alternatively so B*(x/2) &C*(x/2) respectively.
Therefore Ax +(B+C)*x/2=1.
That is x/12 +(1/15+1/20)*x/2=1.
Solving x, we get 7.
Therefore Ax +(B+C)*x/2=1.
That is x/12 +(1/15+1/20)*x/2=1.
Solving x, we get 7.
(6)
Divya said:
5 years ago
Thanks for describing the answer @Alvin.
Ekta Kaushik said:
5 years ago
Thanks @Saisam.
(1)
Ekta Kaushik said:
5 years ago
Thanks @Roshni.
(2)
Mahedi Bipul said:
5 years ago
According to me, the solution is
A * full time work + B * half time work + C * half time work = full part work.
=> (1/12) * x + (1/15) * (x/2) + (1/20) * (x/2) = 1.
x = (120/17) = 7.06
A * full time work + B * half time work + C * half time work = full part work.
=> (1/12) * x + (1/15) * (x/2) + (1/20) * (x/2) = 1.
x = (120/17) = 7.06
(15)
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