Rebecca and Elizabeth are married and will file jointly. Rebecca earns $300,000 from her single-member LLC (a law firm). She reports her business as a sole proprietorship. Wages paid by the law firm amount to $40,000; the law firm has no significant property. Elizabeth is employed as a tax manager by a local CPA firm. Their modified taxable income is $389,800 (this is also their taxable income before the deduction for qualified business income). Determine their QBI deduction for 2021.