Imagine today is your 68th birthday and you decide to retire as of tomorrow morning. You have an annuity that pays you $80,000 per year but without an inflation adjustment. If inflation can be expected to average 6% per year, use the rule of 72 to determine how old you will be when your purchase power has been cut in half to the equivalent of only $40,000. (This question is a slight variation on the way we talk about the Rule of 72 most of the time, but the logic is the same.)

72 years old

76 years old

80 years old

84 years old

88 years old