Determine the tax liability and average tax rate in each of the following cases. Please look up 2020 tax rate table for both married joint and single. This information is easily and readily available online. a. Married taxpayers, who file a joint return, have taxable income of $36,684 b. Single taxpayer has taxable income of $67,342. Provide answers with explanations please. The marginal tax rate for a is 12%. The marginal tax rate for b is 22%