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 3 of 7.
Subash said:
7 years ago
By approx too we can solve this;
a+b+c=1/10,
b+c=1/24,
a=1/10-1/24,
a=17.13,
Near by value 18.
a+b+c=1/10,
b+c=1/24,
a=1/10-1/24,
a=17.13,
Near by value 18.
(5)
Varsha said:
1 decade ago
How did you calculated A's work for 1 day when we do not know any individual work for 1 day?
Shail said:
1 decade ago
@Aditya.
Because a+b.
b+c.
c+a.
So we take out common 2 in the beginning. Got it dear.
Because a+b.
b+c.
c+a.
So we take out common 2 in the beginning. Got it dear.
Shanmugam said:
9 years ago
2( A+B+C) = 15 units.
A+B+C = 7.5 units.
I can't understand this equation @Nikhil.
A+B+C = 7.5 units.
I can't understand this equation @Nikhil.
Meena said:
1 decade ago
We want short cut please anybody solve this shortcut method. Why taken 2 (a+b+C).
Sandeep said:
1 decade ago
While calculating A's 1days work, (1/16-1/24) =1/48.
Why we are taking 1/24 ?
Why we are taking 1/24 ?
Suva das said:
9 years ago
How are you get 1/30+ 1/24+ 1/20 = 15/120 = 1/8?
Please someone explain that.
Please someone explain that.
Shanthi said:
1 decade ago
Yes the same question what kishore asked! why we should consider
2 (a+b+c) ?
2 (a+b+c) ?
Vamsintr said:
1 decade ago
A+B+C=1/16, B+C=1/24.
(A+B+C) - (B+C) =1/16-1/24.
By solving we get 1/48.
(A+B+C) - (B+C) =1/16-1/24.
By solving we get 1/48.
(1)
Gobind Mandal said:
9 years ago
Can anyone please explain m,e that how did you multiply by 48?
3/8 * 48?
3/8 * 48?
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