" vhat rate of simple interest a certain sum will be doubled in "15" years? "

At what rate of simple interest a certain sum will be doubled in 15 years?

At what rate of simple interest a certain sum will be doubled in 14 years

At what rate of simple interest a certain sum will be doubled in 12 years ?

Find the rate of Simple interest by which a given money is doubled in 15 years

2400 becomes 2976 in 3 years at a certain rate of simple interest. What sum of money will become 5016 in 4 years at the same rate of interest?

If a sum of money at a certain rate of simple interest per year doubles in 5 years and at a different rate of simple interest per year becomes three times in 12 years, then the difference in the two rates of simple interest per year is