Question

What sum will amount to rs 9520 at 9% pa in 4 years at simple interest?

Answer 1

$\textbf{Given:}$

$\text{Amount=Rs.9520}$

$\text{Rate of interest, r=9\%}$

$\text{No. of years, n=4 years}$

$\text{Using the formula,}$

$\textbf{Amount=}\bf\;P+\displaystyle\frac{P\,n\,r}{100}$

$\implies\text{Amount=}\;\displaystyle\frac{100P+P\,n\,r}{100}$

$\implies\text{Amount=}\;\displaystyle\frac{100P+P(4)(9)}{100}$

$\implies\text{9520=}\;\displaystyle\frac{100P+36P}{100}$

$\implies\text{9520=}\;\displaystyle\frac{136P}{100}$

$\implies\text{70=}\;\displaystyle\frac{P}{100}$

$\implies\;P=7000$

$\therefore\textbf{The required sum of money is Rs. 7000}$

Answer 2

Step-by-step explanation:

$Amount = Principal( 1+\frac{rate \times time}{100}) \\ 9520 = Principal( 1 + \frac{9 \times 4}{100} ) \\ 9520 = Principal(1 + \frac{36}{100} ) \\ 9520 = Principal(1 + 0.36) \\ 9520 = Principal(1.36) \\ \frac{9520}{1.36} = Principal \\ 7000 = Principal$