Question:
A can do a certain work in the same time in which B and C together can do it. If A and B together could do it in 10 days and C alone in 50 days, then B alone could do it in:
[A].
15 days |
[B].
20 days |
[C].
25 days |
[D].
30 days |
Answer: Option C
Explanation:
| (A + B)’s 1 day’s work = |
1 |
| 10 |
| (A + B + C)’s 1 day’s work = |
|
1 |
+ |
1 |
|
= |
6 |
= |
3 |
. …. (i) |
| 10 |
50 |
50 |
25 |
A’s 1 day’s work = (B + C)’s 1 day’s work …. (ii)
| From (i) and (ii), we get: 2 x (A’s 1 day’s work) = |
3 |
| 25 |
| A’s 1 day’s work = |
3 |
. |
| 50 |
| B’s 1 day’s work |
|
1 |
– |
3 |
|
= |
2 |
= |
1 |
. |
| 10 |
50 |
50 |
25 |
So, B alone could do the work in 25 days.
