Joyce is a single, cash-method taxpayer. On April 11, 2009, Joyce paid $120 with her 2008 state income tax return. During 2009, Joyce had $1,600 in state income taxes withheld. On April 13, 2010, Joyce paid $200 with her 2009 state tax return. During 2010, she had $2,100 in state income taxes withheld from her paycheck. Upon filing her 2010 tax return on April 15, 2011, she received a refund of $450 for excess state income taxes withheld. Joyce had total AGI in 2010 and 2011 of $51,000 and $53,500, respectively. In 2010, Joyce also paid $3,500 in qualified residence interest.
Assume the same facts above, but change the amount of Joyce's mortgage interest to $3,200.
a. What is her taxable income for 2010?
b. What is her AGI for 2011?