A contestant on a quiz show is presented with two questions Q1 and Q2, which she can answer in any order she chooses. Once she chooses which question to try first, she is allowed to go on to the other question only if her answer to the question she chose is correct. The contestant receives $200 for answering Q1 correctly, and $300 for answering Q2 correctly. The probability that she knows the answer to Q1 is 0.7, and the probability that she knows the answer to Q2 is 0.6. In order to maximize her expected winnings, what question should she try first?