One year there were these two guys majoring in Chemistry and who did very well on all of the quizzes, midterms and labs, etc., such that going into the final they had a solid A. These two friends were so confident going into the final that the weekend before finals week (even though the Chem final was on Monday), they decided to go up to Montreal and party with some friends.
So they did. And they had a GREAT time! However, with their hangovers, they overslept and didn't make it back to campus until early Monday morning. Rather than taking the final then, what they did was to find the professor after the final and explain to him why they missed it. They told him that they went up to Montreal for the weekend, and had planned to come back in time to study, but that they had a flat tyre on the way back and didn't have a spare and couldn't get help for a long time and, therefore, were late getting back to campus. The professor thought this over and then agreed that they could make up the final on the following day. The two guys were elated and relieved.
So, they studied that night and went in the next day at the scheduled time. The professor placed them in separate rooms and handed each of them a test booklet and told them to begin. Each student looked at the first problem, which was something simple about molarity and the solution was worth 5 points. "Cool", they thought, "this is going to be easy." They finished that problem and went on to the next. As they turned the page, they were unprepared, however, for what they saw. It said:
(95 points) Which tyre?