You are trying to get the cheapest airfare that you can. You just called up and found that the ticket home will cost $400, and it cannot be refunded or exchanged. You can also buy a ticket for $450, which can be refunded for $430 (and thus costs you $20). The price of tickets will change in one week, and you will have one more chance to buy a ticket. There is a 50% chance that the ticket would cost $300, and a 50% chance that it would cost $600. What should you do to minimize the expected expense? Exercise. Write the Airfare problem as a decision tree, and solvet A simple decision tree analysis add-in for Excel Running XLTree: Launch Excel and open XLTree.xla from the File menu Auto Load Option V Select Add-Ins from the Tools menu in Excel V Select XLTree.xla from list of add-ins and click OK