At Duke University, there were two sophomores taking Organic Chemistry who
did so well on all the quizzes, midterms and labs, etc., 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, even though the Chem final
was on Monday, they decided to go up to University of Virginia and party
with some friends up there...they had a great time. However, with their
hangovers and the hard partying, they overslept all day Sunday and didn't
make it back to Duke 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 the final. They told their Professor they
went to UVA for the weekend and planned to come back in time to study.
Unfortunately, they 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 were late getting
back to campus and didn't have any time to study. The Professor thought it
over and then agreed they could make up the final the following day. The
two guys were elated and relieved. So, they studied that night and went
in the next day at the time the Professor 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?