Answer:
15.16 years (about 1 year and 3 months)
Explanation:
The "Rule of 72" is a way to estimate how long it will take an investment to double (in this case from $11,000 to $22,000). To calculate, simply divide 72 by the fixed interest rate to find number of years:
72/4.75 = 15.16 years (rounded)
