Question

A certain sum becomes rs 8060 in 3 years and 9300 in 5 years at si.what is the rate of interest?

Answer 1

Given : P = ?

            R = ?

            SI = (P*R*T)/100

            8060 - P = (P*R*3)/100--------------------1

            9300 - P = (P*R*5)/100--------------------2

Divide equation (2) by equation (1) :

(9300 - P)/(8060 - P) = 5/3

3(9300 - P) = 5(8060 - P)

27900 - 3P = 40300 - 5P

2P = 12400

=> P = 6200

Now, SI = 8060 - P = 8060 - 6200 = 1860

Therefore, 1860 = (P*R*T)/100

                  1860 = (6200*R*3)/100

                  So, R = 1860/(62*3)

                         R = 10%