Question

Calculate the sum of money on which the compound interest for 2 years be 4 times the simple interest on ₹4715 for 5 years both at the rate 5% per annum

Answer 1

let the sum of money be 'A'

Simple Interest for 5 years, SI = PRT/100 = 4715*5*5 / 100 = Rs. 1178.75

By question, Copound Interest = 4*1178.75 = Rs.4715

We know CI = A(1+R/100)^n - A

or 4715 = A(1 + 5/100)^2 - A [ n=2 years)

or A[ (105/100)^2 - 1] = 4715

or A [(21/20)^2 -1] = 4715

or A(441/400 - 1) = 4715

or A x 41/400 = 4715

A = 400 x 4715 / 41 =Rs. 46000 Ans.

or