please help me find out the answers to both requirements.

Campbell, a single taxpayer, earns $404,000 in taxable income and $2,320 in interest from an investment in State of New York bonds. (Use the U.S. tax rate schedule). Required: a. If Campbell earns an additional $15,800 of taxable income, what is her marginal tax rate on this income? b. What is her marginal rate if, instead, she had $15,800 of additional deductions? (For all requirements, do not round intermediate calculations. Round percentage answers to whole percent.) a. Marginal tax rate % b. Marginal tax rate % 2021 Tax Rate Schedules Individuals Schedule X-Single If taxable income is over: But not over: $ 0 $ 9.950 $ 9,950 $ 40,525 $ 40,525 $ 86,375 $ 86,375 $ 164,925 $ 164,925 $ 209,425 $ 209,425 $ 523,600 $ 523,600 The tax is: 10% of taxable income $995 plus 12% of the excess over $9,950 $4,664 plus 22% of the excess over $40,525 $14,751 plus 24% of the excess over $86,375 $33,603 plus 32% of the excess over $164,925 $47,843 plus 35% of the excess over $209,425 $157,804.25 plus 37% of the excess over $523,600 Schedule Y-1-Married Filing Jointly or Qualifying Widow(er) If taxable income is over: But not over: The tax is: $ 0 $ 19,900 10% of taxable income $ 19,900 $ 81,050 $1,990 plus 12% of the excess over $19,900 $ 81,050 $ 172,750 $9,328 plus 22% of the excess over $81,050 $ 172,750 $ 329,850 $29,502 plus 24% of the excess over $172,750 $ 329,850 $ 418,850 $67,206 plus 32% of the excess over $329,850 $ 418,850 $ 628,300 $95,686 plus 35% of the excess over $418,850 $ 628,300 $168.993.50 plus 37% of the excess over $628,300 Schedule Z-Head of Household If taxable income is over: But not over: The tax is: $ 0 $ 14.200 10% of taxable income $ 14,200 $ 54,200 $1,420 plus 12% of the excess over $14,200 $ 54,200 $ 86,350 $6,220 plus 22% of the excess over $54,200 $ 86,350 $ 164,900 $13,293 plus 24% of the excess over $86,350 $ 164,900 $ 209,400 $32,145 plus 32% of the excess over $164,900 $ 209,400 $ 523,600 $46,385 plus 35% of the excess over $209,400 $ 523,600 $156,355 plus 37% of the excess over $523,600 Schedule Y-2-Married Filing Separately If taxable income is over: But not over: The tax is: $ 0 $ 9.950 10% of taxable income $ 9,950 $ 40,525 $995 plus 12% of the excess over $ 9,950 $ 40,525 $ 86,375 $4,664 plus 22% of the excess over $40,525 $ 86,375 $ 164,925 $14,751 plus 24% of the excess over $86,375 $ 164,925 $ 209,425 $33,603 plus 32% of the excess over $164,925 $ 209,425 $ 314,150 $47,843 plus 35% of the excess over $209,425 $ 314,150 $84,496.75 plus 37% of the excess over $314,150