Question

A sum of money becomes $\frac{4}{3}$ of itself in 6 years at a certain rate of simple interest find the rate of interest.

Answer 1

Let the rate of interest is r and sum of money be x
it becomes $\frac{4x}{3}$ in 6 yrs
So, SI in 6 yrs =$\frac{4x}{3}-x=\frac{x}{3}$
As we know that SI =$\frac{ptr}{100}$, where p=x, t=6.
or $\frac{x}{3}=\frac{x\times 6\times r}{100}$
or $r=\frac{50}{9}$
$\therefore r=5.56\%$ (approx)
So, rate of interest 5.56%