Question: The income tax-free yield on a certain municipal bond is 7% per year. This translates into approximately a 5% annual yield if the municipal bond's interest had been taxable in the 28% income tax bracket [7% (1 - 0.28) approx. = 5%]. Compare the future worth of the two situations (i.e., non-taxable versus taxable interest) when $15,000 is deposited annually for 30 years. What is the learning "take away" of this problem?