All tax calculations should be based on the 2020 Tax Rate Schedules. Figures should be rounded to the nearest dollar. Percentages should be rounded to the nearest whole percentage (e.g., 32% instead of 32.2%)

Mortgage interest. Casimir owns both a principal residence and a vacation home. He personally vacations at the vacation home for 100 days and rents it at fair rental value to strangers for 100 days. The rest of the year it is not used. He uses the IRS method to allocate expenses. The principal residence and the vacation home were both acquired in 2011, using in part mortgage debt. The mortgage on the principal residence was $180,000 throughout the year; Casimir paid $8,000 in interest on this mortgage. The mortgage on the vacation home was $400,000 throughout the year; Casimir paid $20,000 in interest on this mortgage. What is the largest amount Casimir can take as an itemized deduction for mortgage interest?