Question

49. At what rate percent simple interest Rs 1 will amount to Rs 9 in 60 years ​

Answer 1

Answer:

Let the rate of interest be r%. Then the interest get compounded each year at the rate of r%. Formula for compound interest = (1+r)^n - where n is number of years. So (1+r)^20 = 9 => 1+r = 9^(1/20) = 1.116 approx => r = 0.116 = 11.6