Question

On what sum will the compound interest for 2 years at 4% per annum be 5712?
A man invests 1200 for two years at compound interest. After one year the money
amounts to 1275. Find the interest for the second year correct to the nearest rupee.​

Answer 1

Compound interest=principal×{(1+ rate of interest/100)^time -1}

or, 5712 = principal× { (1+ 4/100)^2-1}

or, 5712 = principal × { (26/25)^2-1}

or, 5712 = principal × {(676/625) - 1}

or, 5712 = principal × 51/625

therefore, principal = 5712×625/51

=₹ 70000