The professor makes no promise at all. In fact, she announces in class that she will be unable to attend the next session because her favorite racehorse, Preexisting Duty, is running in the third race at the local track and she wants to be there. The students are crushed at the idea of missing a class. Sam wails, "Don't do this to us, Professor! I'll pay you twenty bucks if you'll be here to teach us." Other students chime in, and in a groundswell of tears and emotion, the students promise a total of $1,000 if Professor will do her job. She agrees. When she arrives to teach the next class, 25 suddenly sad students refuse to pay, and she sues. Who wins and why?