Chuck, a single taxpayer, earns $77,200 in taxable income and $10,000 in interest from an investment in City of Heflin bonds. (Use the U.S. tax rate schedule.) Required: If Chuck earns an additional $40,300 of taxable income, what is his marginal tax rate on this income? What is his marginal rate if, instead, he had $40,300 of additional deductions?