Question

At what rate percent per annum will the simple interest on a sum of money be 2/5 of the principal amount in 10 years ?

Answer 1

Dear Student,

$$\begin{gathered} Lettheprincipalbe5units \\ Then,Simpleinterestin10years=\frac{2}{5}\times 5=2units \\ Weknow,SimpleInterest=\frac{P\times r\times t}{100} \\ 2=\frac{5\times r\times 10}{100} \\ \mathit{r}\mathbf{=}\mathbf{4}\mathbf{\%}\mathbf{} \end{gathered}$$

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