The Solution

Two guys were taking Chemistry at the University of Alabama. They were doing
well in the class and thought that going into the final they had a solid "A".
They were so confident that the weekend before finals week, they went to the
University of Tennessee to party with some friends.
They had a great time. However, with hangovers and everything, they overslept
all day Sunday and didn't make it back to Alabama until early Monday morning,
the day of the exam.
Rather than taking the final then, they found their professor after the final
to explain to him why they missed the final.
They told him that they went up to the University of Tennessee 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, so they were late in getting back to campus.
The professor told them they could make up the final on the following day.
They were elated and relieved. At the final, the professor placed them in
separate rooms, handed each of them a test booklet and told them to begin.
The first problem, worth 5 Points, was something simple about Molarity &
Solutions. "Cool," they thought. "This is going to be easy."
The next problem was worth 95 Points. It asked: "Which tire?"