Four university friends were so confident in their abilities that the weekend before their final exams, they decided to get out of town and party with some friends. After all the partying, they slept all day Sunday and didn’t make it back home until early Monday morning.
Rather than taking the exam then, they decided to find their professor afterwards and explain to him why they missed it.
They explained that they had gone away for the weekend with the plan to come back and study but, unfortunately, they had a flat tyre on the way back, didn’t have a spare and couldn’t get help for a long time. As a result, they missed the exam.
The professor thought it over and then agreed they could do exam the following day. The friends were elated and relieved.
They studied that night and went in the next day at the time the professor 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, worth five points. It was fairly simple. “Cool,” they all thought at the same time, each one in his separate room. “This is going to be easy.”
Each finished the problem and then turned the page. On the second page was written: “(For 95 points): Which tyre?”