Suppose your firm earns $4 million in taxable income. What is the firm's tax liability? What is the average tax rate? What is the marginal tax rate? If you are considering a project that will increase the firm's taxable income by $1 million, what tax rate should you use in your analysis? Calculate above questions under the old (2017) tax code Tax rates ("buckets) and new flat rate .15 tax rate for first 50,000 Dollars .25 50,000- 75,000 .34 75,000-100,000 .39 100,000-335,000 over 335,000 .34 Under the new (2018) tax code, the average rate = marginal rate = a flat 21%