This past fall semester, at Duke University, there were two sophomores who
were taking Organic Chemistry and who did pretty well on all of the quizzes
and the 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 University of Virginia and party with some friends
up there. So they did this and had a great time.  However, with their
hangovers and everything, they overslept all day Sunday and didn't make it
back to Duke until early Monday morning.

Rather than taking the final then, what they did was to find Professor
Aldric after the final and explain to him why they missed the final. They
told him that they went up to UVA for the weekend, and had planned to come
back in time to study, but that they had 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.  So, 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?