A certain sum becomes Rs. 1020 in 5 years and Rs. 1200 in 8 years at simple interest. What is the value of principal? 

The simple interest on an amount of 2,800 at the end of 3 years is Rs 420. What will be the simple interest at Rs 3200 for the same rate and for the same period?

Mohit borrowed Rs. 22000 at 5% simple interest repayable in 5 equal installments. What will be the annual installment payable by him?

How much simple interest will be received in 10 years on the amount of Rs. 1600? If the rate of interest is 7.25 percent per annum.

Equal sum of money are lent to X and Y at 7.5 % per annum for a period of 4 years and 5 years respectively. If the difference in interest, paid by them was 150, the sum lent to each was 

If the instalments are paid at the end of every year, what annual payment will discharge a debt of Rs. 7,200 due in 3 years at 20% per annum simple interest?

In how many years will Rs 4600 amount to Rs 5428 at 3 % per annum simple interest?

A person invested a sum of Rs. 18,600 at x% per year and another sum that is twice the former at (x+2)% per year, both at simple interest. If the total interest earned on both investments for $$ {3{1\over 2}}$$ years is Rs.23,110.50, then the rate of  interest per year on the second investment is: