During 2015, the Smiths and the Jones both filed joint tax returns. For the tax year ended December 31, 2015, the Smiths' taxable income was

$128,000, and the Jones had total taxable income of $64,000.

TABLE 1.2: Tax Rates and Income Brackets for Joint Returns (2015)
	Taxable Income
Tax Rates	Joint Returns
10%	$0 to $18,150
15%	$18,151 to $73,800
25%	$73,801 to $148,850
28%	$148,851 to $226,850
33%	$226,851 to $405,100
35%	$405,101 to $457,600
39.6%	Over $457,600

a. Using the federal tax rates given in Table 1.2, for married couples filing joint returns, calculate the taxes for both the Smiths and the Jones.

b. Calculate and compare the ratio of the Smiths' to the Jones' taxable income and the ratio of the Smiths' to the Jones' taxes. What does this demonstrate about the federal income tax structure?

Please write out every step, and formula. Thank you.