Flat Tire Joke

At the Univ. of Texas, there were four sophomores taking chemistry and
all of them had an "A" so far. These four friends were so confident,
that the weekend before finals they decided to visit some friends and
have a big party. They had a great time, but after all the hearty
partying, they slept all day Sunday and didn't make it back to Austin
until early Monday morning.

Rather than taking the final then, they decided that after the final
they would explain to their professor why they missed it. They said that
they had visited friends, but on the way back they had a flat tire. As a
result, they missed the final. The professor agreed they could make up
the final the next day.

The guys were excited and relieved. They studied that night for the
exam. The Professor placed them in separate rooms and gave them a test
booklet. They quickly answered the first problem, worth 5 points. " Cool " ,
they thought!

Each one in a separate room, thinking this was going to be easy....then
they turned the page.

On the second page was written ....

....

....

....

....


.... For 95 points: Which tire?