Annual compound interest rate \((r)\) \(= \cfrac{2.5 \times 100}{100}\% = 2.5\%\) Principal \((P) = ₹64,000\) Time \((n) = 2\) years \(\therefore\) Total compound amount \(= P\left(1 + \cfrac{r}{100}\right)^n\) \(= 64000\left(1 + \cfrac{2.5}{100}\right)^2\) \(= 64000\left(1 + \cfrac{25}{1000}\right)^2\) \(= 64000\left(\cfrac{41}{40}\right)^2\) \(= 64000 \times \cfrac{41}{40} \times \cfrac{41}{40}\) \(= 40 \times 41 \times 41\) \(= ₹67,240\) \(\therefore\) Compound interest amount = ₹67,240 − ₹64,000 = ₹3,240