Mrs. Singer owns a profitable sole proprietorship. For each of the following cases, use a Schedule SE, Form 1040, to compute her 2018 self-employment tax and her income tax deduction for such tax. 

a. Mrs. Singer’s net profit from Schedule C was $51,458. She had no other earned income. 

b. Mrs. Singer’s net profit from Schedule C was $51,458, and she received a $100,000 salary from an employer. 

c. Mrs. Singer’s net profit from Schedule C was $51,458, and she received a $137,000 salary from an employer.