Question: A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With help of C, they did the job in 4 days only. Then, C alone can do the job in:
[A].
10
[A].
| 9 | 1 | days |
| 5 |
[B].
| 9 | 2 | days |
| 5 |
[C].
| 9 | 3 | days |
| 5 |
[D].
Answer: Option C
Explanation:
| (A + B + C)’s 1 day’s work = | 1 | , |
| 4 |
| A’s 1 day’s work = | 1 | , |
| 16 |
| B’s 1 day’s work = | 1 | . |
| 12 |
| C’s 1 day’s work = | 1 | – | 1 | + | 1 | = | 1 | – | 7 | = | 5 | . | ||||
| 4 | 16 | 12 | 4 | 48 | 48 |
| So, C alone can do the work in | 48 | = 9 | 3 | days. |
| 5 | 5 |