The simple interest on a loan is $\frac{16}{25}$ of the principal, and the number of years equals the rate per cent per annum. What is the rate?

Explanation

1. 01

   Let the rate be R% and the time R years. Then $\text{SI} = \frac{P \times R \times R}{100}$.

2. 02

   $\frac{R^2}{100} = \frac{16}{25}$, so $R^2 = 64$.

3. 03

   $R = 8\%$, and the time is 8 years.