On a sum, simple interest at the annual rate of 10 percent for 8 years is Rs. 8000. What will be the compound interest on the same sum at the annual rate of 10 percent (compounding annually) for 3 years?

Correct option is D

Given:
Simple interest for 8 years at 10% = Rs. 8000
Rate of interest (R) = 10% per annum
Time for compound interest = 3 years
Compounding annually
Formula Used:
Simple Interest = (Principal× Rate× Time) / 100
Compound Interest = Principal×[$$(1 + Rate/100)^{Time}$$​ - 1]
Solution:
First, find the principal from the simple interest formula:
8000 = (P×10×8) / 100
P = 10000
Now, use the compound interest formula:
Compound Interest = 10000×[$$(1 + 10/100)^3$$​ - 1]
= 10000×[$$(1.1)^3$$​ - 1] = 10000×[1.331 - 1] = 10000×0.331 = Rs. 3310