Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 15)
15.
Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is:
Answer: Option
Explanation:
| Part filled in 2 hours = | 2 | = | 1 |
| 6 | 3 |
| Remaining part = |  |
1 - | 1 |  |
= | 2 | . |
| 3 | 3 |
 (A + B)'s 7 hour's work = |
2 |
| 3 |
| (A + B)'s 1 hour's work = | 2 |
| 21 |
C's 1 hour's work = { (A + B + C)'s 1 hour's work } - { (A + B)'s 1 hour's work }
| = | |
1 | - | 2 | |
= | 1 |
| 6 | 21 | 14 |
C alone can fill the tank in 14 hours.
Discussion:
44 comments Page 3 of 5.
Ramya said:
1 decade ago
(A+B+C) - (A+B) can give you the answer.
(A+B+C) =1/6 and (A+B+C) in 2hrs=2/6 and remaining part 1-2/6=2/3.
So (A+B) in 7 hrs is 2/ (3*7) =2/21.
1/6-2/21=1/14 so answer is 14.
(A+B+C) =1/6 and (A+B+C) in 2hrs=2/6 and remaining part 1-2/6=2/3.
So (A+B) in 7 hrs is 2/ (3*7) =2/21.
1/6-2/21=1/14 so answer is 14.
(1)
Soundharya saravanan said:
1 decade ago
A+B+C = 6 hrs after working 2 hrs.
A+B+C = 2 hrs.
So the remaining work is = 1-2/6 = 2/3.
A+B = 7 hrs.
(2/(3*7) = 2/21.
1/6-2/21 = 1/14.
Answer is: 14 hrs.
A+B+C = 2 hrs.
So the remaining work is = 1-2/6 = 2/3.
A+B = 7 hrs.
(2/(3*7) = 2/21.
1/6-2/21 = 1/14.
Answer is: 14 hrs.
Nfl said:
1 decade ago
@Sharvari.
A+B+C = 2/6= 1/3 ..remaining part of cistern filled by A+B by 7 hours.
Remaining part 2/3 in 7 hours.. for exact 1 hour by A+B= 2/3*1/7=1/21.
A+B+C = 2/6= 1/3 ..remaining part of cistern filled by A+B by 7 hours.
Remaining part 2/3 in 7 hours.. for exact 1 hour by A+B= 2/3*1/7=1/21.
Namrata said:
9 years ago
As we know x/a + x/b + x/c = x/6.
Write equation as;
(X/6) * 2 + (x/6 - x/c) * 7 = x.
After solving this equation you will get answer as 14.
Write equation as;
(X/6) * 2 + (x/6 - x/c) * 7 = x.
After solving this equation you will get answer as 14.
Sri vidhya said:
9 years ago
Why we need to calculate the final step for that one hour for A & B & C and A & B?
Naveen said:
1 decade ago
(A+B)'s 7 hour work is 2/3.
(A+B)'s 1 hour work is(2/3)/7 = 2/3*7 = 2/21.
(A+B)'s 1 hour work is(2/3)/7 = 2/3*7 = 2/21.
M.v.krishna said:
1 decade ago
Part filled in 2 hours= 2/6.
This step is not clear. Please explain.
This step is not clear. Please explain.
(1)
Hemanth said:
9 years ago
Hi, I am not getting this, please give me a proper explanation.
A.D. said:
7 years ago
Please tell me, how to solve this question using LCM method?
Harshitha said:
1 decade ago
Can you explain the step (A+B) 's 1 hour work = 2/21.
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