Question

If the ratio of a principal and the amounts for 5 years is 5 : 6, then find the rate of simple interest per annum.​

Answer 1

$\textbf{Given:}$

$\textsf{In 5 years, Principal : Amount = 5 : 6}$

$\textbf{To find:}$

$\textsf{Rate of interest}$

$\textbf{Solution:}$

$\textbf{Simple interest formula:}$

$\mathsf{Simple\;interest=\dfrac{Pnr}{100}}$

$\textsf{As per given data,}$

$\mathsf{Principal:Amount=5:6}$

$\implies\mathsf{\dfrac{P}{P+\dfrac{Pnr}{100}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{1+\dfrac{nr}{100}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{1+\dfrac{5r}{100}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{1+\dfrac{r}{20}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{\dfrac{20+r}{20}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{20}{20+r}=\dfrac{5}{6}}$

$\implies\mathsf{120=5(20+r)}$

$\implies\mathsf{120=100+5r}$

$\implies\mathsf{20=5r}$

$\implies\mathsf{r=\dfrac{20}{5}}$

$\implies\boxed{\mathsf{r=4\%}}$

$\textbf{Find more:}$

If the sum of interest on rs850 for 3years and rs1250 for 4years at the same rate of interest is rs302 find the percentage of si per annum

https://brainly.in/question/16801176

Difference between CI and SI on rs. 8400 for 2 years at 21 at same rate of interest per year. Find rate of interest

https://brainly.in/question/26563854

Answer 2

$\textbf{Given:}$

$\textsf{In 5 years, Principal : Amount = 5 : 6}$

$\textbf{To find:}$

$\textsf{Rate of interest}$

$\textbf{Solution:}$

$\textbf{Simple interest formula:}$

$\mathsf{Simple\;interest=\dfrac{Pnr}{100}}$

$\textsf{As per given data,}$

$\mathsf{Principal:Amount=5:6}$

$\implies\mathsf{\dfrac{P}{P+\dfrac{Pnr}{100}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{1+\dfrac{nr}{100}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{1+\dfrac{5r}{100}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{1+\dfrac{r}{20}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{1}{\dfrac{20+r}{20}}=\dfrac{5}{6}}$

$\implies\mathsf{\dfrac{20}{20+r}=\dfrac{5}{6}}$

$\implies\mathsf{120=5(20+r)}$

$\implies\mathsf{120=100+5r}$

$\implies\mathsf{20=5r}$

$\implies\mathsf{r=\dfrac{20}{5}}$

$\implies\boxed{\mathsf{r=4\%}}$