Four university students decided to go out the night before their final exam. They drink too much, get home late, don’t hear their alarms going off and completely miss the exam.
The students go to their professor, explaining this elaborate story that they were on their way to the final but the car they were travelling in got a flat tyre. They beg their professor to be allowed to retest the exam. After hearing their pleas and giving it careful consideration, the professor agrees.
The day of the make-up exam arrives. All four of the students arrive on time. They are prepared for the exam.
The professor looks a the students, he looks at his watch, then says, “You may begin the test.”
The four students open their final exam booklet, but to their surprise there is only one question:
“Which tyre was flat?”