Question

14.
A sum of money amounts to Rs. 1210 in two years and
Rs. 1331 in three years at compound interest (interest
being compounded annually). The interest rate per
annum is
a) 8
c) 10.5 d) 11
b) 10

Answer 1

see the attachment........

Answer 2

Answer:

Required rate of interest is 10%.

So,option b is the correct answer.

Step-by-step explanation:

Given,A sum of money amounts to Rs. 1210 in two years and Rs. 1331 in three years.

We know,

Amount = C.l+p$= p {(1 + \frac{r}{100})}^{t}$

Where,

$p =$Principle

$t =$time

$r =$rate of interest.

According to question,

$\frac{p {(1 + \frac{r}{100})}^{3}}{p {(1 + \frac{r}{100})}^{2}} = \frac{1331}{1210}$

$\frac{ {(1 + \frac{r}{100})}^{3}}{{(1 + \frac{r}{100})}^{2}} = \frac{ {11}^{3} }{ {11}^{2} \times 10}$

$1 + \frac{r}{100} = \frac{11}{10}$

$\frac{r}{100} = \frac{1}{10}$

$r = 10$

Therefore rate of interest is 10%.