Answer:
Every 7.86 years the investment doubles.
Step-by-step explanation:
Giving the following information:
Interest rate= 8.9% compounded annually
To determine the number of years to double the money, we can use the rule of 70:
The rule of 70 is a means of estimating the number of years it takes for an investment or your money to double.
Number of Years to Double= 70/Annual Rate of Return
Number of Years to Double= 70/8.9
Number of Years to Double= 7.86 years
Every 7.86 years the investment doubles.