This year Randy paid $29,950 of interest on his residence. (Randy borrowed $476,000 to buy his residence, which is currently worth $526,000.) Randy also paid $3,150 of interest on his car loan and $5,175 of margin interest to his stockbroker (investment interest expense). How much of this interest expense can Randy deduct as an itemized deduction under the following circumstances?

a. Randy received $2,720 of interest this year and no other investment income or expenses. His AGI is $75,000.

b. Randy had no investment income this year, and his AGI is $75,000.