Relevant costs: Paul and Paula Petroceli were trying to decide whether to go to the symphony or the baseball game. They have two non-refundable tickets for the symphony that cost $40 each. Tickets for the baseball game can be purchased for $20 each. Parking for the symphony is free, but parking at the baseball game costs $6. To attend either event, they have to hire a baby sitter that will cost them $30. Compare the costs of the two alternatives and indicate which is more expensive for the couple.