SOLUTION: Investors sometimes use the rule of 72 to determine the time required to double an investment. If 72 is divided by the annual earned on an investment, the result approximates the n
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Question 402040: Investors sometimes use the rule of 72 to determine the time required to double an investment. If 72 is divided by the annual earned on an investment, the result approximates the number of years needed to double the investment. For example, an investment earning 6% annual interest will double in value approximately every 72/6 = 12 years.
(a) Approximate the number of years required to double an investment earning 9% annual interest.
(b) If an investment of $10,000 earns 12% annual interest, approximate the value of the investment after 18 years. Answer by rfer(16322) (Show Source):
(