The difference between the simple interest and the compound interest on a sum of money for 3 years at 10% per annum is ₹ 558. Find the sum.

The difference between the compound interest for 1 year, compounded half-yearly and the simple interest for 1 year on a certain sum of money at 10% per annum is ₹ 360. Find the sum.

At what rate per cent per annum will ₹ 3,000 amount to ₹ 3,993 in 3 years, the interest being compounded annually?