Question

Find the time, in years, in which rupess 4000 will produce rupess 630.50 as compound interest at 5% p.a. interest being compounded anually.

Answer 1

ci= p{ (1+r/100)^n - 1}
630.50= 4000{ (1 + 5/100)^n -1}
630.50/4000=(21/20)^n -1
4630.5/4000=(21/20)^n
9261/8000=(21/20)^n
(21/20)^3=(21/20)^n
n=3 years