A bank pays Simple Interest at 4% per annum for the first 2 years, then at 5% per annum for the next 3 years, and 6% per annum for the period beyond 5 years. If a man gets ₹2,050 as interest at the end of 8 years, what was his initial investment?

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?