Use Table 3.6. (Do not round intermediate calculations. Enter the average tax rate as a percent rounded to 1 decimal place.) 0. What would be the marginal tax rate for a married couple with income of $89.500 ? b. What would be the average tax rate for a married couple with income of $89.500 ? c. What would be the marginal tax rate for an unmarried taxpayer with income of $89,500 ? d. What would be the average tax rate for an unmarried taxpayer with income of $89,500