Kiran lent ₹5,00,000 to Kishore at a rate of 12% per annum compounded annually for 3 years. Kishore then lent the same amount to Kavya on simple interest at a rate of 15% per annum for 3 years. What is the difference between the interest earned by Kishore and the interest he owes to Kiran after 3 years?

A sum becomes 25 times of itself when invested for 48 years at r% simple interest per annum. Find the compound interest earned if Rs. 51,200 is invested at r% per annum when interest is compounded half-yearly, for 1.5 years.

Simple interest on a certain sum at 4% per annum for 2 years is ₹80. What is the compound interest on the same sum for the same period at the same rate?