The compound interest on a certain sum of money for 3 years, compounded annually, at a rate of interest of 10% per annum is ₹1,324. The sum is:

₹4,000

The formula that we used here is :-

Amount = P$(1 \;+\; \frac{R}{100})^t$

Compound interest = Amount - Principal

1324 = [ P × ( 1 +  \(\frac{10}{100}\) )³ ] - P

1324 = P [ \(\frac{11}{10}\)  × \(\frac{11}{10}\)  × \(\frac{11}{10}\) - 1]

1324 = P [ \(\frac{1331}{1000}\) - 1]

1324 = P [ \(\frac{1331 - 1000}{1000}\)]

1324 = P [ \(\frac{331}{1000}\)]

P = Rs. 4000

So, Initial sum is Rs. 4000