The Long Walk

One hundred teenage boys (picked at random from a large pool of applicants) participate in an annual walking contest called "The Long Walk." Each Walker must maintain a speed of at least four miles per hour; if he drops below this speed for a total of 30 seconds (all at once or spread out over time), he receives a verbal warning. Walkers can eliminate a warning by walking for an hour without being warned. If, however, a Walker with three warnings slows down again, he is "ticketed".