Question: A does 80% of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?
[A].
23 days |
[B].
37 days |
[C].
37 |
[D].
40 days |
Answer: Option C
Explanation:
| Whole work is done by A in |
|
20 x |
5 |
|
= 25 days. |
| 4 |
| Now, |
|
1 – |
4 |
|
i.e., |
1 |
work is done by A and B in 3 days. |
| 5 |
5 |
Whole work will be done by A and B in (3 x 5) = 15 days.
| A’s 1 day’s work = |
1 |
, (A + B)’s 1 day’s work = |
1 |
. |
| 25 |
15 |
| B’s 1 day’s work = |
|
1 |
– |
1 |
|
= |
4 |
= |
2 |
. |
| 15 |
25 |
150 |
75 |
| So, B alone would do the work in |
75 |
= 37 |
1 |
days. |
| 2 |
2 |
