Tick (✓) the correct answer:
The compound interest on Rs 4000 at 10% per annum for 2 years 3 months, compounded annually, is
(a) Rs 916
(b) Rs 900
(c) Rs 961
(d) Rs 896
(c) Rs 961
Here, $A=P \times\left(1+\frac{R}{100}\right)^{2} \times\left(1+\frac{\frac{1}{4} R}{100}\right)$
$=$ Rs. $4000 \times\left(1+\frac{10}{100}\right)^{2} \times\left(1+\frac{\frac{1}{4} \times 10}{100}\right)$
$=$ Rs. $4000 \times\left(\frac{100+10}{100}\right)^{2} \times\left(\frac{40+1}{40}\right)$
$=$ Rs. $4000 \times\left(\frac{110}{100}\right)^{2} \times\left(\frac{41}{40}\right)$
$=$ Rs. $4000 \times\left(\frac{11}{10}\right) \times\left(\frac{11}{10}\right) \times\left(\frac{41}{40}\right)$
$=$ Rs. $(11 \times 11 \times 41)$
$=$ Rs. 4961
$\therefore$ Compound interest $=$ amount $-$ principal $=$ Rs $(4961-4000)=$ Rs 961