Algebra and Trigonometry and Their Applications

Math 148 Autumn Quarter, 2001

Instructor: Sergei Chmutov

Bonus problem. The Rule of 72
10 points extra credit

The rule of 72 allows you to find the number of years required to double your money at a given interest rate compounded annually. See the site "Why it works" for a kind of mathematical explanation and for "The rule of 69" for continuously compounded interest.

Find (and provide an explanation) for the similar rules for interest compounded

(Answers should be accurate to three decimal places.)