Dev lent Rs. 8000 to Jairam for 17 years and Rs. 4700 to Karnik for 16 years on simple interest at the same rate of interest and received Rs. 21120 in all from both of them as interest. The rate of interest per annum is:

What is the ratio of simple interest earned on certain amount at the rate of 12% p.a. for 9 years and that for 12 years?

The difference between simple interest on a certain sum at the rate of 6% per annum for 5 years and 6 years is 25.8. What is the sum (in Rs)?

What is the ratio of simple interest earned on certain amount at the rate of 12% for 6 years and that for 12 years?

R borrowed Rs. 1,200 at 13% per annum simple interest. What amount will R pay to clear the debt after 5 years?

A sum of Rs 4000 becomes Rs 7000 in 6 years at simple interest. If the rate of interest becomes double of itself, then what will be the amount (in Rs) after 6 years?

A sum of Rs 800 becomes Rs 1000 in 2 years at simple interest. What is the per annum rate of interest (in percent)?

Sachin lent out Rs 60000 in two parts, first at 4% and the second at 10% interest. The yearly average interest comes out to be 6.4%. What are the amounts (in Rs) that were lent at 4% and 10% respectively?

Rs. x invested at 8% simple interest per annum for 5 years yields the same interest as that on Rs. y invested at 7.5% simple interest per annum for 6years. Find x : y.