-
Find the rate percent per annum, if Rs. 2000 amounts to Rs. 2,315.25 in a year and a half,
interest being compounded half yearly.
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- 11.5%
- 10%
- 5%
- 20%
Correct Option: B
As per the given in question ,
| Time = | years = 3 half years | |
| 2 |
Rate = 2R% per annum = R% per half year
| ∴ Amount = Principal – |  | 1 + |  | Time | |
| 100 |
| ⇒ 2315.25 = 2000 | | 1 + | | 3 | |
| 100 |
| ⇒ | = | | 1 + | | 3 | ||
| 200000 | 100 |
| ⇒ | = | | 1 + | | 3 | ||
| 8000 | 100 |
| ⇒ | | | 3 | = | | 1 + | | 3 | ||
| 20 | 100 |
| ⇒ | | 1 + | | 3 | = | | 1 + | | 3 | ||
| 20 | 100 |
| ⇒ 1 + | = 1 + | ||
| 20 | 100 |
| ⇒ | = | ||
| 100 | 20 |
| ⇒ R = | = 5% per half year | |
| 20 |
∴ Required rate = 10% per annum
