Laugh of the day

Came across this one, thought it was pretty funny. Enjoy!

Four students didn't study for an exam on the following day. They go see the professor in the morning and tell him that they were driving and one of the wheels broke off and they crashed, and they ask if they can take the exam the following morning. The professor agrees. The next day the four students are placed in four diferent rooms so as to prevent them from cheating. The professor hands them each a sheet of paper with a question worth 5%. The students glad they studied all night answer the question with no difficulty. The professor then hands them a second sheet of paper with a question worth 95%: which wheel broke off on the car?