Could I please get some help with calculation?

Click here to access the 2020 tax rate schedule. If required, round the tax liability to the nearest dollar. When required, round the average rates to four decimal places before converting to a percentage (i.e. .67073 would be rounded to .6707 and entered as 67.07%). a. Chandler, who files as a single taxpayer, has taxable income of $122,000. Tax liability: Marginal rate: % Average rate: % b. Lazare, who files as a head of household, has taxable income of $81,000. Tax liability: Marginal rate: Average rate: 000000 % %