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A can do 1/2 of a work in 9 days while B can do 1/3 of the same work in 6 days. How long would it take for A and B together to complete the work?
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- 8 days
- 9 days
- 10 days
- 7 days
Correct Option: B
A’s 9 days’ work
| = | 2 |
∴ A’s 1 day’s work
| = | = | |||
| 2 × 9 | 18 |
| B’s 6 days’ work = | 3 |
∴ B’s 1 day’s work
| = | = | |||
| 3 × 6 | 18 |
∴ (A + B)’s 1 day’s work
| = | + | = | = | |||||
| 18 | 18 | 18 | 9 |
∴ A and B both together will
complete the work in 9 days.
Aliter : Using Rule 2,
A’s 1 day work
| = | = | days | ||
| 2 × 9 | 18 |
Required time taken
| = | x + y |
| = | 18 + 18 |
| = | = 9 days | 36 |
