You are a contestant on "Who Wants to be a Millionaire?" You have already answered the $250,000 question correctly and now must decide if you would like to answer the $500,000 question. You can choose to walk away at this point with $250,000 in winnings or you may decide to answer the $500,000 question. If you answer the $500,000 question correctly, you can then choose to walk away with $500,000 in winnings or go on and try to answer the $1 million question. If you answer the $1 million question correctly, the game is over and you win $1 million. If you answer either the $500,000 or the $1 million question incorrectly, the game is over immediately and you take home only $32,000.

A feature of the game is that you have three "lifelines." At this point (after answering the $250,000 question), you have already used two of these lifelines, but you have the "phone a friend" lifeline remaining. With this option, you may phone a friend and obtain advice on the correct answer to a question before giving your answer. You may use this option only once (i.e., you can use it on either the $500,000 question or the $1 million question, but not both). Since some of your friends are smarter than you are, "phone a friend" significantly improves your odds of answering a question correctly. Without "phone a friend," if you choose the answer the $500,000 question you have a 65% chance of answering correctly, and if you choose to answer the $1 million question you have a 50% chance of answering correctly. With "phone a friend," you have an 80% chance of answering the $500,000 question correctly and a 65% chance of answering the $1 million question correctly.

Use PrecisionTree to construct and solve a decision tree to decide what to do. What is the best course of action, assuming that your goal is to maximize your expected winnings?