Pics That Make You LOL

There were two sophomores at Duke University who were taking Organic Chemistry and who did well enough on all of the quizzes and the midterms and labs, etc., such that they had solid 'A's going into the final exam. These two friends were so confident going into the final that they decided to go up to University of Virginia and party with some friends on the weekend before finals week, even though the Chem final was on Monday.
They did this and had a great time. However, with their hangovers and everything, they overslept all day Sunday and they didn't make it back to Duke until early Monday morning. Rather than taking the final then, they went Professor Aldric after the final and explained to him why they missed the final. They told him that they went up to UVA for the weekend, and they had planned to come back in time to study, but that theyhad a flat tire on the way back and didn't have a spare and couldn't get help for a long time and so were late getting back to campus.
Aldric thought this over and then agreed that they could make up the final on the following day. The two guys were elated and relieved. They studied that night and went in the next day at the time that Aldric had told them. He placed them in separate rooms and handed each of them a test booklet and told them to begin. They looked at the first problem, which was something simple about free radical formation and was worth 5 points. "Cool" they thought, "this is going to be easy." They did that problem and then turned the page. They were unprepared, however, for what they saw on the next page.
It said, "(95 points) Which tire?"