Question

A man invests Rs 3,000 for three years at compound interest. After one year, the money amounts to Rs 3,240. Find the rate of interest and the amount (to the nearest rupee) due at the end of 3 years

Answer 1

For ,
$N=1years$
$P=Rs3,000$
$A=Rs3,240$
$=>S.I.=A-P=Rs240$
We have $S.I.=\frac{PNR}{100}=\frac{3,000\times 1\times R}{100}=Rs240$
$=>R=8$ %
And on interest being compounded for $3$ years and $R=8$ %, $Amount=P{(1+\frac{R}{100})}^N=3,000\times {(1+\frac{8}{100})}^3=3,000\times \left({1.08}^3\right)=3,779.136$ or $Rs3,779$