Simple Interest - General Questions

A sum of Rs. 17,000 earns a simple interest of Rs. 3,400 in 2 years. What is the rate of interest per annum?

At 8% per annum simple interest, what principal yields Rs. 480 as interest in 2 years?

A sum of money amounts to Rs. 9,800 in 4 years and to Rs. 11,200 in 6 years at simple interest. What is the sum?

What is the simple interest on Rs. 18,000 at 15% per annum for 4 years?

A sum of money amounts to Rs. 2,268 in 2 years and to Rs. 2,520 in 5 years at simple interest. What is the sum?