A sum of money trebles itself in 15 years, 6 months. In how many years would it double itself?
Q1. A sum of money trebles itself in 15 years, 6 months. In how many years would it double itself?
Answer: 7 years 9 months
Explanation: Simple interest: the sum gains 2P in 15.5 years, giving rate = 2/15.5 per year. To gain P (double), time = 1 ÷ (2/15.5) = 7.75 years = 7 years 9 months.