Tammy, a single taxpayer, has a part-time job at BigCo, a company in which she has no ownership interest. In addition, she owns and operates LittleCo, a sole proprietorship that is a qualified trade or business. Tammy is paid wages of $40,000 by BigCo and has $100,000 in qualified business income from LittleCo. She has no other items of income or loss and $25,000 of itemized deductions.

a) What is her qualified business income deduction?

b) Assume the same facts as in the problem directly above, except that Tammy does not have a part-time job at BigCo. What is her qualified business income deduction?