Rs.8000 become Rs.9261 in a certain interval of time at the rate of 5% per annum of C.I. Find the time ?

Amount = 9261 p = 8000
rate = 5%
A = p [ 1 + r / 100]ⁿ
9261 = 8000[1 + 5/100]ⁿ
=> 9261 / 8000 = [21 / 20]ⁿ
=> [21 / 20]³=[21 / 20]ⁿ
on comparing n = 3 so it will take 3years