3) Based on the amounts of taxable income below, determine the federal income tax due for the

2015 tax year on each amount assuming the taxpayers are married filing a joint return. Also, for each amount of taxable income, compute the average tax rate and the marginal tax rate. For your calculations, use the 2015 Tax Rate Schedules, which can be found at https://www.irs.gov/irb/2014-47_IRB/ar14.html.

(a) $30,000

(b) $100,000

(c) $375,000

(d) $600,000