Mary (age 40) is single and provides more than 50% of the support of Tammy (a family friend), Jen (a niece, age 18) and John (a nephew, age 18). Both Tammy and Jen live with Mary, but John (a French citizen) lives in Canada. Mary earns a salary of $90,000, contributes $5,000 to a traditional IRA, and receives sales proceeds of $15,000 for an RV that cost $65,000 and was used for vacations. She has $8,200 in itemized deductions. Compute Marys 2020 tax liability including the child and dependent tax credit if applicable.

United States Tax Code of 2020 in use here. Thank you.