If Julius has a 28% tax rate and a 12% after-tax rate of return, $61,000 of income in three years will cost him how much tax in today's dollars?

Assume that John's marginal tax rate is 40%. If a city of Austin bond pays 5.70% interest, what interest rate would a corporate bond have to offer for John to be indifferent between the two bonds?

Assume that Marsha is indifferent between investing in a city of Destin bond that pays 3.8% interest and a corporate bond that pays 5.8% interest. What is Marsha's marginal tax rate?