Question

A sum of money placed at compound interest doubles itself in 5yr. It will amount to 8 times itself at the same rate of interest in how many yrs ??

Answer 1

5year= 2times
We need 8 times so we have to do power 3 of 2.. and mutiply by the same no. In time means 3
5*3 = 2³
15= 8 times
Answer- 15 years