Final answer:
The rule of 72 is an approximation that provides an estimate of the number of years needed to double your money given a particular rate of investment.
Step-by-step explanation:
The rule of 72 is an approximation that provides an estimate of the number of years needed to double your money given a particular rate of investment. It is calculated by dividing the number 72 by the annual growth rate. For example, if you have a growth rate of 6%, it would take approximately 72/6, or 12 years, for your money to double.