Question

A sum of money doubles itself at compound interest in 10 years. In how many years will it be eight times?

Answer 1

Explanation:

A sum of money doubles itself at a compound interest in 15 years . In how may years it will become 8 times ?? If the sum doubles (x2) in 15 years, then it to become 2*2*2 = 8 times as large it should double three times, so three 15 years time period are needed, which is 3*15 = 45 years.