Determine the tax liability, marginal tax rate, and average tax rate in each of the following cases. Use the Tax Tables to compute tax liability. Required: a. Married taxpayers, who file a joint return, have taxable income of $31,916. b. Single taxpayer, has taxable income of $66,829. Note: For all requirements, round "Average tax rate" to 2 decimal places. Tax liability Marginal tax rate Average tax rate a. 12% % b. $ 10,319 22% %