I have been trying to solve this problem for almost forty minutes, however, I can't seem to find the answer. Thanks in advance. If you could please provide an explanation that would be greatly appreciated!

HW1-Ch1 i Saved Help Save & Exit Submit Check my work 2 Chuck, a single taxpayer, earns $76,300 in taxable income and $11,500 in interest from an investment in City of Heflin bonds. (Use the U.S. tax rate schedule.) Required: 1.67 points a. If Chuck earns an additional $40,000 of taxable income, what is his marginal tax rate on this income? b. What is his marginal rate if, instead, he had $40,000 of additional deductions? eBook (For all requirements, do not round intermediate calculations. Round percentage answers to 2 decimal places.) Print References a. Marginal tax rate b. Marginal tax rate % %