The interest earned on Rs. 4800 at a rate of R% compounded annually is Rs. 1008 after 2 years. What would be the simple interest earned on the same amount at the rate of (R + 5)% per annum 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?