At what rate per cent per annum compound interest will ₹ 6,250 amount to ₹ 7,290 in 2 years?

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

A certain sum of money amounts to ₹ 7,260 in 2 years and to ₹ 7,986 in 3 years, interest being compounded annually. Find the rate per cent per annum.

A town has 15625 inhabitants. If the population of this town increases at the rate of 4% per annum, find the number of inhabitants of the town at the end of 3 years.