Thread: The Professor

There were four university chemistry students who had
sailed through all their exams. They were so confident
that on the weekend before their finals, they decided to
have a big party in the next town.

They had such a great time partying, they slept all day
Sunday and didn't make it back home until Monday morning.
Rather than take the exam, they decided that after the
exam, they would explain to their professor why that had
missed it.

After explaining to their professor that they had been
visiting friends and on the way home, had a flat tyre and
as a result, had missed the exam. The prof agreed they
could make up the exam the next day.

The professor placed them in separate rooms and gave
them the test papers. They quickly answered the first
question worth 5%.

Thinking this was going to be easy, they turned to page
two upon which was written -

For 95%: Which tyre?