Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 23)
23.
A and B can do a piece of work in 30 days, while B and C can do the same work in 24 days and C and A in 20 days. They all work together for 10 days when B and C leave. How many days more will A take to finish the work?
Answer: Option
Explanation:
| 2(A + B + C)'s 1 day's work = |  |
1 | + | 1 | + | 1 |  |
= | 15 | = | 1 | . |
| 30 | 24 | 20 | 120 | 8 |
| Therefore, (A + B + C)'s 1 day's work = | 1 | = | 1 | . |
| 2 x 8 | 16 |
| Work done by A, B, C in 10 days = | 10 | = | 5 | . |
| 16 | 8 |
| Remaining work = | |
1 - | 5 | |
= | 3 | . |
| 8 | 8 |
| A's 1 day's work = | |
1 | - | 1 | |
= | 1 | . |
| 16 | 24 | 48 |
| Now, | 1 | work is done by A in 1 day. |
| 48 |
| So, | 3 | work will be done by A in | |
48 x | 3 | |
= 18 days. |
| 8 | 8 |
Discussion:
61 comments Page 4 of 7.
Sanjay said:
8 years ago
They all work togeather when (B+C) on leave then how can we take 10 days work for every person?
Mithun said:
8 years ago
GIVEN: A+B B+C A+C.
FORMULA: 2(A+B+C) = (A+B)(B+C)(A+C)
=2(1/8)
=1/16
GET A:
A+B+C=1/16, B+C=1/24.
(A+B+C) - (B+C) =1/16-1/24.
By solving we get A as 1/48.
10/16 + x/48=1 [ABC worked for 10days]
x=18.
FORMULA: 2(A+B+C) = (A+B)(B+C)(A+C)
=2(1/8)
=1/16
GET A:
A+B+C=1/16, B+C=1/24.
(A+B+C) - (B+C) =1/16-1/24.
By solving we get A as 1/48.
10/16 + x/48=1 [ABC worked for 10days]
x=18.
Maruf Hossain said:
8 years ago
Awesome explanation, Thanks @Nikhil.
VIGNESH said:
8 years ago
Super explanations, thanks @nikhil.
Manu said:
1 decade ago
Nice work guys. I really didn't understand how we calculated A's one days work 1/48 but after reading discussions I got the answer, nice work by all of you.
Dinesh said:
1 decade ago
See dude...
ab, bc, ac
So add three (a+b) + (b+c) + (a+c) = so we need (a+b+c).
Add all.
2a + 2b + 2c
2 (a + b + c) = now we add na.
ab, bc, ac
So add three (a+b) + (b+c) + (a+c) = so we need (a+b+c).
Add all.
2a + 2b + 2c
2 (a + b + c) = now we add na.
Shanthi said:
1 decade ago
Yes the same question what kishore asked! why we should consider
2 (a+b+c) ?
2 (a+b+c) ?
Ramkumar said:
1 decade ago
Ramkumar:.
Good question but easy to understand.
Good question but easy to understand.
Lalitha said:
1 decade ago
Wow can we take 1/24 (1/16-1/24) ?
Gurjit said:
1 decade ago
why subtract 1/16-1/24 on the above equation a=1/30
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