Question: X can do a piece of work in 40 days. He works at it for 8 days and then Y finished it in 16 days. How long will they together take to complete the work?
[A].
15 days
20 days
26 days
[A].
| 13 | 1 | days |
| 3 |
[B].
[C].
[D].
Answer: Option A
Explanation:
| Work done by X in 8 days = | 1 | x 8 | = | 1 | . | ||
| 40 | 5 |
| Remaining work = | 1 – | 1 | = | 4 | . | ||
| 5 | 5 |
| Now, | 4 | work is done by Y in 16 days. |
| 5 |
| Whole work will be done by Y in | 16 x | 5 | = 20 days. | ||
| 4 |
| X’s 1 day’s work = | 1 | , Y’s 1 day’s work = | 1 | . |
| 40 | 20 |
| (X + Y)’s 1 day’s work = | 1 | + | 1 | = | 3 | . | ||
| 40 | 20 | 40 |
| Hence, X and Y will together complete the work in | 40 | = 13 | 1 | days. | ||
| 3 | 3 |