Question : The simple interest on a sum of money is $\frac{8}{25}$ of the sum. If the number of years is numerically half of the rate percent per annum, then the rate percent per annum is:

Question : In what least number of complete years does a sum of money become more than four times itself at the rate of 50% per annum on simple interest?

Question : In how much time will a sum of Rs. 10200 amount to Rs. 19125 at the rate of 12.5% per annum at simple interest?

Question : If a sum of money becomes Rs. 4000 in 2 years and Rs. 5500 in 4 years and 6 months, at the same rate of simple interest per annum, the rate of simple interest is:

Question : A person borrowed some money at simple interest. After 4 years, he returned $\frac{9}{5}$th of the money to the lender. What was the rate of interest?