Question

In how many years, will the compound interest on Rs. $1000$ at the rate of $10\%$ p.a. be Rs.$210$

• A. $1$ year
• B. $1.5$ years
• C. $2$ years
• D. $2.5$ years

Answer 1

Answer: (C)

$2$ years

Given that $P=1000$, $R=10\%$ and $C.I.=210$

$T=?$

We have $C.I.=P{(1+\frac{R}{100})}^T-P$

$\Rightarrow 210=1000{(1+\frac{10}{100})}^T-1000$

Simplifying we get,

$\Rightarrow \frac{1210}{1000}={\left(\frac{110}{100}\right)}^T$

$\Rightarrow {\left(\frac{11}{10}\right)}^T=\frac{121}{100}=\frac{{11}^2}{{10}^2}$

$\Rightarrow T=2years$