The simple interest on a sum of money at 10% per annum for 4 years is ₹3,200. What will be the amount (in ₹) of the same sum for the same period at the same rate of interest when the interest is compounded annually?

11,712.80

Simple interest =10%

S.I. for 4 years  = 10 × 4 = 40%

Therefore,

⇒ 40% of Principal = 3200

⇒ Principal = \(\frac{3200}{40}\) × 100 = Rs. 8000

Now,

Amount at (C.I.) = P (1+\(\frac{R}{100}\))^t

                        = 8000 (1+\(\frac{10}{100}\))⁴

                        = 8000(\(\frac{11}{10}\))⁴

                        = Rs. 11712.80