A man invested Rs. 2,400 at 5% per annum and Rs. 5,400 at 9% per annum simple interest. What total amount (in Rs.) will he receive from both investments combined after 6 years?

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?