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A sum of money at a certain rate per annum of simple interest doubles in the 5 years and at a different rate becomes three times in 12 years. The lower rate of interest per annum is
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- 15%
- 20%
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15 3 % 4 -
16 2 % 3
- 15%
Correct Option: D
The sum gets doubled in 5 years and tripled in 12 years.
Clearly rate of interest for 12 years will be lower.
Let Principal be p.
| Then, Rate = | |
| Principal × Time |
| Rate = | |
| p × 12 |
| Rate = | |
| 3 |
| Rate = 16 | % | |
| 3 |
Second method to solve this question :
| R1 = | × 100% = 20% | |
| 5 |
| R2 = | × 100% | |
| 12 |
| R2 = 16 | % | |
| 3 |
| ⇒ Lower rate of interest = 16 | % | |
| 3 |
