Taxes are paid on net profits, so income applied to fixed and variable costs is not taxed. Since the fixed costs are $200 per week, and ABC audio clears $5 on each set of headphones, the fixed costs will be met once ABC has sold 40 sets. For each $10 of income for every additional set sold, ABC pays a 20% tax on the $5 cleared after variable costs are accounted for, leaving $4 profit. So, to make $400 profit for the week, ABC audio will need to sell an additonal 100 sets. Thus, accounting for fixed costs, variable costs, and taxes, ABC must sell 140 sets of headphones per week to generate $400 in profit.