Answer: 35%
Step-by-step explanation:
First and foremost, we've to calculate the amount that will be taxed on $400000 which will be:
= $46628.50 + ($400000-$204100) × 35%
= $46628.50 + ($400000-$204100) × 0.35
= $46628.50 + $68565
= $115193.5
When earns an additional $15,000 of taxable income, this means her total taxable income will be:
= $400,000 + $15,000
= $415000
Therefore, the tax amount on $415000 will be:
= $46628.5 + ($415000 - $204100) × 35%
= $46628.5 + ($415000 - $204100) × 0.35
= $120443.5
Marginal Tax rate will then be calculated as:
= change in Tax / change in Taxable income
= ($120443.5 - $115193.5) / ($415000 - $400000)
= $5250 / $15000
= 35%