Question

If the simple interest on a certain sum of money is $\frac{4}{25}$ of the sum and the rate percent equals the number of years, then the rate of interest per annum is:

• A. 2%
• B. 3%
• C. 4%
• D. 6%
• E. None of the above

Answer 1

The correct option is C 4%

Let the principal be Rs x. then the simple interest $\left(I\right)=\frac{4}{25}x.$
Let the rate of interest p.a. be r%, then time (T)=r years.
$\therefore R=\frac{100\times I}{P\times T}\Rightarrow r=\frac{100\times \frac{4}{25}x}{x\times r}\Rightarrow r^2=\frac{400}{25}orr=\frac{20}{5}=4\%$