A certain sum amounts to ₹6,425 after 3 years and to ₹8,800 after 8 years at the same rate percent per annum at simple interest. What will be the amount of the same sum after 5 years at the same rate at simple interest?

A sum becomes 2215 of itself in 6 years at simple interest. Find the rate of interest per annum.

In how many years will a sum of ₹5,500 amount to ₹6,600 at a simple interest rate of 5% per annum?

A sum of money amounts to ₹16000 in 6 years at simple interest of 25 percent per annum. What will be the total interest for 6 years?