Smart Professor!
There were four sophomores taking Organic Chemistry. They were doing well on all the quizzes, midterms and labs, etc. Each had an "A" so far for the semester. The four friends were so confident that the weekend before finals, they decided to drive down to the University of San Diego and party with some friends.
They had a great time, but after all the hearty partying, they slept all day Sunday and didn't make it back until early Monday morning.
Rather than taking the final then, they decided to find their professor after the final and explain to him why they missed it. They told him they had gone to USD for the weekend and planned to come back in time to study but, unfortunately, had a flat tire on the way back, didn't have a spare, and couldn't get help for a long time. As a result, they missed the final.
The professor thought it over and then agreed they could make up the final the following day. The guys were elated and relieved. They studied that night and went in the next day at the time the professor had told them.
He placed them in separate rooms, handed each of them a test booklet and told them to begin.
They looked at the first problem, worth 5 points. It was something simple about free radical formation. Cool, they thought! Each one, in his separate room, thought the exam was going to be easy After finishing the first problem they turned the page. On the second page was written:
For 95 points:
Which tire?