Question

A sum at compound interest doubles itself in 15 years. in how much years will it become 8 times

Answer 1

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.
So the answer is 45 plz do mark as brainliest