Lily $($self$-$employed$)$ went from her office in Portland, Maine, to Lisbon, Portugal, on business.

While there, she spent part of the time on vacation.

How much of the $$5,000$ airfare can she deduct based on the following assumptions:

a$.$ Lily was gone five days $($i$.$e$.,$ three days business and two days personal$).$

b$.$ Lily was gone five weeks $($i$.$e$.,$ four weeks business and one week personal$).$

c$.$ Lily was gone five weeks $($i$.$e$.,$ three weeks business and two weeks personal$).$