Problem $3-38($LO $3-2,$ LO $3-3)($Static$)$

Isabel, a calendar$-$year taxpayer, uses the cash method of accounting for her sole proprietorship. In late December she received a $$20,000$ bill from her accountant for consulting services related to her small business. Isabel can pay the $$20,000$ 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 $12$ percent on her investments.