- Home
- Standard 13
- Quantitative Aptitude
6.Interest
medium
What will be the compound interest on a sum (In ₹) of ₹ $25000$ after $3$ years at the rate of $12 \%$ per annum?
A
$9000.30$
B
$9720$
C
$10123.20$
D
$10483.20$
Solution
C.I. after 3 years $=25000\left[\left(1+\frac{12}{100}\right)^{3}-1\right]=25000\left[\left(\frac{28}{25}\right)^{3}-1\right]$
$=\frac{25000}{25^{3}}\left(28^{3}-25^{3}\right)=\frac{40}{25}(28-25)\left(28^{2}+25^{2}+28 \times 25\right)$
$=\frac{40 \times 3}{25}(784+625+700)=\frac{24}{5} \times 2109$
$=4.8 \times 2109=₹ 10123.20$
Standard 13
Quantitative Aptitude