A certain sum invested at 10% per annum compound interest compounded half yearly, amounts to Rs.551.25 at the end of one year. The sum is:

525 500 550 575

500

Given rate = 10% Time = 1 year ( The interest is compounded half yearly then, ) Effective rate will be = 5 + 5 + \(\frac{5 × 5}{100}\) = 10.25% Amount = Principle + interest = 100% + 10.25% = 110.25% 110.25% = 551.25  100% = 500(Sum)