Question

the sum amount is rs. 9680 in 2years and rs. 10648 in 3years compounded annually. find the sum and rate of interest per annum .

Answer 1

10%

Let the sum be Rs. P and rate of interest be R% per annum. Then,

P\left ( 1+\frac{R}{100} \right )^{2} = 9680 .........(1)

P\left ( 1+\frac{R}{100} \right )^{3} = 10648 ......(2)

On dividing equation (2) by (1) :

1+\frac{R}{100} = \frac{10648}{9680}

=> \frac{R}{100} = \frac{10648}{9680} - 1

=> \frac{R}{100} =\frac{10648 - 9680}{9680}

=> \frac{R}{100} = \frac{968}{9680} = \frac{1}{10}

=> R = \frac{1}{10}\times 100 = 10\%