At what simple interest rate percent per annum will a sum of money double in 8 years?

What is the amount for a sum of money Rs.7500 at 6% rate of interest C.I. for 2 years?

A sum invested at 7% simple interest per annum grows to Rs 540 in 5 years. The same amount at 9% simple interest per annum in 3 years will grow to be-

A sum of money invested at simple interest triples itself in 8 years and becomes n times in 20 years. What is the value of n?

What is the compound interest on Rs. 2500 for 2 years at rate of interest 4% per annum?

The difference between simple interest and the compound interest compounded annually at the rate of 12% per annum on ₹ 5,000 for two years will be :