abel, a calendar$-$year taxpayer, uses the cash method of accounting for her sole proprietorship. In late December she received a $$42,000$ bill from her accountant for consulting services related to her small business. Isabel can pay the $$42,000$ bill anytime before January $30$ of next year without penalty. Assume her marginal tax rate is $37$ percent this year and next year, and that she can earn an after$-$tax rate of return of $7$ percent on her investments.

Required:

What is the after$-$tax cost if Isabel pays the $$42,000$ bill in December?

What is the after$-$tax cost if Isabel pays the $$42,000$ bill in January? Use Exhibit $3\mathrm{.}1.$

Note: Round your answer to the nearest whole dollar amount.

Based on requirements a and b$,$ should Isabel pay the $$42,000$ bill in December or January?