A Sum of money at simple interest doubles in 10 years. In how many years, will it amount to 4 times itself?
Q1. A Sum of money at simple interest doubles in 10 years. In how many years, will it amount to 4 times itself?
Answer: 30 years
Explanation: Doubles in 10 years means rate = 10% SI; to become 4 times, interest needed = 3P; time = 3P/(P×0.10) = 30 years.