Final Exam

At Duke University, their were four sophomores taking chemisty and all of them had "A" so far. The weekend before the finals they decided to visit a friend and have a big party. They had such confidents that they didn't need to study. It was agreat party and they slept all day Sunday and did't meet it back to Duke until early Monday morning. Rather than taking the final then, they decided that after the final, they would explain to their professor why they missed it. They said that they visited a friend but on the way back they had a flat tire. As a result, they missed the final. The Professor agreed they could make up the final the next day. The guys were excited and relieved. They studied hard that night. The Professor placed them all in sparated rooms and gave them all a test booklet. They quickly answered the first problem worth 5 points. Cool they thought, each one in a separated room, thinking this this was going to be easy, then they turned the page. On the second page was written for 95 points WHICH TIRE?