1. Stephanie has taxable income of $48,200 and a tax liability of $6,400. If Stephanies income increases by $4,000, her tax liability will be $7,280.

a. What is her average tax rate (as a percent rounded to the nearest whole number) on the $48,200 of income?

b. What is her marginal tax rate (as a percent rounded to the nearest whole number) on the $48,200 of income?

2. Geoffrey filed his tax return 2 months and 8 days late and had not requested an extension of time for filing. Geoffrey's return indicated that he is to receive a $600 refund in taxes. Calculate the amount of Geoffrey's penalty for failure to file his tax return on time, assuming the failure to file was not fraudulent.