Question

A sum of money becomes rs 13380 after 3 years and rs 20070 after 6 years on compound interest the sum is

Answer 1

Let the sum be Rs. x. 

Then           x(1+R100)3=13380x(1+R100)3=13380

and            x(1+R100)6=20070x(1+R100)6=20070

On dividing we get 

(1+R100)3(1+R100)3=(2007013380)(2007013380)=(32)(32)

..˙..˙  x32x32=13380

=>   x=(13380×23)x=(13380×23)=8920

Hence, the sum is Rs. 8920