How to get 100% in Final Examination

I heard about this professor in a well-known school who was about to give a final examination to his students. This was the most important exam of the year. Before he distributed the test papers, he told his students how honored and glad he was of them. The professor gives emphasis to that because they worked so hard, he would offer them a deal. He said that those who wanted an automatic passing grade of 80% the exam would just have to raise their hands. They didn't even have to take the exam. One student raised his hand slowly, tailed by other students, until about half of the class raised their hands and chose not to take the exam. The professor said they could already leave the room and have their free time instantly. The students who took the offer were so happy and felt so relieved and thankful. 

In the meantime, the remaining students who opted to take the final exam waited for the test papers to be distributed. The professor, standing in front, encouraged the students who were left behind. He told them that he believed they'd do great things in life. He even stressed that they should continue to strive hard and do their best in whatever they would do in life.

The professor then distributed the test papers and told the class to start by reading the instructions. To the students' surprise, the test paper contained only two sentences: "Congratulations! You just made a score of 100!"

We think the professor decided to give a grade of 100% because he believed that the students who decided to stay believed they could do much more and could have much more. They have probably prepared for the examination and aimed to get a perfect score anyway. Thus, the professor rewarded them with a grade of 100%.