Question

The simple interest on Rs 45,000 in 3 years in Rs 13,500. What is the rate of interest?

Answer 1

Interest = Rs 13,500
Principal = Rs 45,000
Number of years = 3 years
Let rate of interest be R
Simple Interest$=\frac{\mathrm{Principal}\times \mathrm{Rate}\times \mathrm{Time}}{100}$
$$\begin{gathered} \Rightarrow 13,500=\frac{45000\times R\times 3}{100} \\ \Rightarrow 13,500=\frac{135000R}{100} \\ \Rightarrow 135000R=13500\times 100 \\ \Rightarrow R=\frac{13500\times 100}{135000} \\ \Rightarrow R=10\%\mathrm{per}\mathrm{annum}. \end{gathered}$$

∴ The rate of interest is 10% per annum.