QB_PH_GA_020: Quantitative Aptitude

A sum of money invested under compound interest compounded annually amounts to Rs. 4,840 in 2 years and Rs. 5,324 in 3 years. What is the annual rate of interest in percent?

Correct Answer

### Step-by-Step Derivation & Verification: 1. **Compound Interest Progression**: In successive compounding periods: $A_{n+1} = A_n \left(1 + \frac{R}{100}\right)$ 2. **Ratio of Consecutive Years (Year 2 to Year 3)**: $\frac{A_3}{A_2} = 1 + \frac{R}{100}$ $\frac{5324}{4840} = 1 + \frac{R}{100}$ 3. **Evaluation**: $1.10 = 1 + \frac{R}{100} \implies \frac{R}{100} = 0.10 \implies R = 10\%$ 4. **Official Answer**: 10.