B. 3 years
Feedback Let Principal = P, Rate = R% per annum, Time = n years.
When interest is compounded Annually total amount can be calculated by using the formula,
Total Amount = P(1 + R/100)n
Given that, P = Rs.8000, R = 20% per annum
We have to find the time period during which the amount will be Rs.13824
i.e., Rs.13824 = 8000 x (1 + 20/100)^n
13824/8000 = (120/100)n
(24/20)^3 = (12/10)n
(12/10)^3 = (12/10)n
Therefore, n = 3.
Hence the required time period is 3 years.