Question

Seema invested an amount of Rs16000 for two years at
compound interest and received an amount of Rs17640
on maturity. What is the rate of interest?​

Answer 1

I7640 = l6ooo (1+r/loo)^2

(I+r/loo)^2 =17640/16 ooo

= 1764 / l6oo

I+r/loo=42/4o (square roots,

r/loo=42/4o-I

r/loo=2/4o

r = 200/4o=5

rate 5%

Answer 2

let the rate of interest is =r

now , according to the problem....

$17640 = 16000(1 + \frac{r}{100}) {}^{2} \\ \frac{17640}{16000} = (1 + \frac{r}{100}) {}^{2} \\ \sqrt{ \frac{17640}{16000} } - 1 = \frac{r}{100} \\ r = 5$

the rate is 5 percent