Expenses incurred to own and maintain a vacation property must be allocated between personal use and rental use. When a taxpayer rents his vacation home, all of the following describe personal-use days EXCEPT:

A co-worker rents the property for $50 a day. The fair rental price is $75 a day.

A friend rents the property for $500 a week, which is considered a fair rental price. In exchange, the owner stays at the friend's lakefront property for $750 a week.

The owner's mother lives in the home all year and pays $600 a month in rent, which is considered a fair rental price. The property is the mother's principal residence.

The owner's brother rents the property for one week at $500. The property was not considered his home. The fair rental price is $500 a week.