Two college seniors had a week of exams coming up.
However, they decided to party instead. So, when
they went to the test, they decided to tell the
professor that their car had broken down the night
before due to a very flat tyre and they needed a
bit more time to study.

The professor told them that they could have
another day to study. That evening, both of the
boys crammed all night until they were sure that
they knew just about everything.

Arriving to class the next morning, each boy was
told to go to separate classrooms to take the
exam. Each shrugged and went to two different
parts of the building. As each sat down, they read
the first question. "For 5 points, explain the
contents of an atom."

At this point, they both thought that this was
going to be a piece of cake, and answered the
question with ease.

Then, the test continued... "For 95 points, tell
me which tyre it was."