eBook Susan and Stan Britton are a married couple who file a joint income tax return, where the tax rates are based on the tax table 3.5. Assume that their taxable income this year was $278,000. Do not round intermediate calculation. their federal tax liability? Round your answer to the nearest cent. a. What s b. What their marginal tax rate? Round your answer to two decimal places. % C. What is their average tax rate? Round your answer to two decimal places. 2017 Individual Tax Rates TABLE 3.5 Plus This Percentage on the Excess over the Base (Marginal Rate) 10.0% 15.0 Average Tax Rate at Top of Bracket 10.0% 13.8 25.0 20.4 28.0 24.3 33.0 29.0 35.0 29.0 39.6 39.6 Single Individuals You Pay This If Your Taxable Amount on the Income Is Base of the Bracket Up to $9,325 $ 0 $9,325-$37,950 932.50 $37,950-591,900 5,226.25 $91,900-$191,650 18,713.75 $191,650-$416,700 46,643.75 $416,700-5418,400 120,910.25 Over $418,400 121,505.25 Married couples Filing Joint Returns You Pay This If Your Taxable Amount on the Income is Base of the Bracket Up to $18,650 $ 0 $18,650-$75,900 1,865.00 $75,900-$153,100 10,452.50 $153,100-$233,350 29,752.50 $233,350-$416,700 52,222.50 $416,700-$470,700 112,728.00 Over $470,700 131,628.00 Plus This Percentage on the Excess over the Base (Marginal Rate) Average Tax Rate at Top of Bracket 10.0% 15.0 10.0% 13.8 25.0 19.4 28.0 22.4 33.0 27.1 35.0 28.0 39.6 39.6