An information systems consultant who lives in Dallas must spend the majority of the month of March onsite with a client in San Diego. Her travel schedule for the month is as follows:

Leave Dallas Leave San Diego

Monday, March 2 .......Friday, March 6

Monday, March 9 .......Thursday, March 12

Tuesday, March 17 ........Friday, March 20

Monday, March 23 ........Wednesday, March 25

The usual round-trip ticket price between Dallas and San Diego is $750. However, the airline offers a 25% discount if the dates on a round-trip ticket cover less than 7 nights and include a weekend. A35% discount is offered for round-trip tickets covering 10 or more nights, and a 45% discount is available for round-trip tickets covering 20 or more nights. The consultant can purchase four round-trip tickets in any manner that allows her to leave Dallas and San Diego on the days indicated.

a. Draw a network flow model for this problem.

b. Implement the problem in a spreadsheet and solve it.

c. What is the optimal solution? How much does this save for four full-cost roundtrip tickets?