Melissa recently paid $760 for round-trip airfare to San Francisco to attend a business conference for three days. Melissa also paid the following expenses: $370 fee to register for the conference, $365 per night for three nights' lodging, $250 for meals in restaurants, and $300 for cab fare.

a. What amount of these costs can Melissa deduct as business expenses?

b. Suppose that while Melissa was on the coast, she also spent two days sightseeing the national parks in the area. To do the sightseeing, she paid $1,710 for transportation, $1,285 for lodging, and $475 for meals during this part of her trip, which she considers personal in nature. What amount of the total costs can Melissa deduct as business expenses?

c. Suppose that Melissa made the trip to San Francisco primarily to visit the national parks and only attended the business conference as an incidental benefit of being present on the coast at that time. What amount of the airfare can Melissa deduct as a business expense?