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A and B together can complete a work in 15 days. A is 50% more efficient worker than B. How long will A take to complete the work alone ?
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- 20 days
- 21 days
- 21.4 days
- 22.5 days
- None of these
Correct Option: E
Ratio of the work of A and B
done in 1 day = 3 : 2
[∵ B's work doen = x (let), then
| A's work done = | x = | x | ||
| 100 | 2 |
| So, (A : B)'s work done = | x : x or 3 : 2] | 2 |
∵ Work done by A and B together in 1 day
| = | 15 |
| ∴ A’s 1 day’s work = | × | |||
| 15 | 5 |
| = | 25 |
Hence, A alone will finish the work in 25 days.
Aliter : Using Rule 22,
| Here, n = | 2 |
because A is 50% more efficient than B.
D = 15
Time taken by A
| = |  |  | × D | n |
| = | | | × 15 = 25 days | 3/2 |
