Question:
Mark (✓) against the correct answer:
If the compound interest on a certain sum for 2 years at 10% per annum is Rs 1050, the sum is
(a) Rs 3000
(b) Rs 4000
(c) Rs 5000
(d) Rs 6000
Solution:
(c) Rs 5000
Here, $A=P \times\left(1+\frac{R}{100}\right)^{n}$
$=P \times\left(1+\frac{10}{100}\right)^{2}$
$=P \times\left(\frac{110}{100}\right)^{2}$
$=P \times\left(\frac{11}{10}\right) \times\left(\frac{11}{10}\right)$
Now, $C I=A-P$
$\Rightarrow$ Rs. $1050=\frac{121 p}{100}-P$
$=\frac{121 P-100 P}{100}$
$=\frac{21 P}{100}$
$\therefore P=\mathrm{Rs} \frac{1050 \times 100}{21}=\mathrm{Rs} 5000$