Using the corporate tax rate schedule given in Table 1.4, perform the following:

a. Find the marginal tax rate for the following levels of corporate earnings before taxes: $15,000; $60,000; $90,000; $200,000; $400,000; $1 million; and $20 million. b. Plot the marginal tax rates (measured on the y axis) against the pretax income levels (measured on the x axis). Explain the relationship between these variables.