Question

Calculate the compound interest on Rs. $15,000$ in $3$ years. If the rates of interest for successive years be $6\%$, $8\%$ and $10\%$ respectively.

• A. Rs. $3,879.20$
• B. Rs. $3,889.20$
• C. Rs. $3,789.20$
• D. Rs. $3,689.20$

Answer 1

The correct option is B Rs. $3,889.20$

Simple Interest $I=\frac{PNR}{100}$
Here for first year,
$P=Rs.15,000$
$N=1$ year
$R=6$ %
So, Interest at the end of 1st year $I=\frac{15,000\times 1\times 6}{100}=Rs.900$
And for second year,
$P=Rs.15,000+Rs.900=Rs.15,900$
$N=1$ year
$R=8\%$
$I=\frac{15,900\times 1\times 8}{100}=Rs.1272$
And, for third year,
$P=Rs.15,900+Rs.1,272=Rs.17,172$
$N=1$ year
$R=10\%$
$I=\frac{17,172\times 1\times 10}{100}=Rs.1,717.2$
So, total interest $=Rs.900+Rs.1,272+Rs.1,717.2=Rs.3,889.20$