A certain sum is lent on simple interest at 4% p.a. for 3 years, 8% p.a. for the next 4 years, and 12% p.a. beyond 7 years. If for a period of 11 years, the total simple interest obtained is Rs. 27,600, then the sum (in Rs.) 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?