Problem 1-37 (LO 1-3) Campbell, a single taxpayer, earns $288,000 in taxable income and $6,000 in interest from an investment in State of New York bonds. (Use the U.S. tax rate schedule) Required: ces a. If Campbell earns an additional $20,000 of taxable income, what is her marginal tax rate on this income? b. What is her marginal rate if, instead, she had $20,000 of additional deductions? (For all requirements, do not round intermediate calculations.) Marginal tax rate b Marginal tax rate