Question

a sum of money on simple interest gets doubled in 8 years.how many years will it take for the sum of money to become four times of the initial amount if the rate of interest remains the same​

Answer 1

16 years

Let the sum of money be x.Then, in the first 8 years the sum of money will become double I.e. 2x.And in the next 8 years it will become 2(2x) I.e. 4x.Which means that the sum of money will become 4 times in (8+8)years I.e. 16 years.