'A' lent Rs. 5000 to 'B' for 2 years and Rs. 3000 to 'C' for 4 years on simple interest at the same rate of interest and received Rs. 2200 in total from both of them as interest. The rate of interest per annum is:

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?