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If I purchased 11 books for $ 100 and sold 10 books for $ 110, the percentage of profit per book sold is
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- 10%
- 11·5%
- 17·3%
- 21%
Correct Option: D
If a articles are bought for $ p
and b articles are sold for $ q,
then
| Gain% = |  | qa - pb |  | × 100 | |
| pb |
| Gain% = | | 11 × 110 - 10 × 100 | | × 100 | |
| 10 × 100 |
| Gain % = | × 100 = 21% | 1000 |
Second method to solve this question :
Here, a = 11, p = 100 and b = 10, y = 110
| Gain% = | | aq - bp | | × 100% | |
| bp |
| Gain% = | | 11 × 110 - 10 × 100 | | × 100 | |
| 10 × 100 |
| Gain% = | × 100% = 21% | 1000 |
