Rhea Xu is a self-employed professional singer. She resides in a rented apartment and uses one room exclusively as a business office. This room includes 225 of the 1,500 square feet of living space in the apartment. Ms. Xu performs in recording studios and concert halls, but she conducts all of the administrative duties with respect to the business in her home office. This year, Ms. Xu’s apartment rent was $48,000. She paid $5,200 to a housekeeping service that cleaned the entire apartment once a week and $2,000 for renter’s insurance on the apartment furnishings. Compute Ms. Xu’s home office deduction assuming that

a. Her net profit before the deduction was $300,000. 

b. Her net profit before the deduction was $4,000.