5. Chuck, a single taxpayer, earns $70,000 in taxable income and $10,000 in interest from an investment in City of Heflin bonds. If Chuck earns an additional $40,000 of taxable income, what is his marginal tax rate on this income?

6. Chuck, a single taxpayer, earns $70,000 in taxable income and $10,000 in interest from an investment in City of Heflin bonds. If Chuck claims an additional $40,000 of deductions, what is his marginal tax rate on this income?

7. Jorge and Anita, married taxpayers, earn $145,000 in taxable income and $40,000 in interest from an investment in City of Heflin bonds. Using the U.S. tax rate schedule for married filing jointly, how much federal tax will they owe?