A blonde reports for her final exam, which consists of yes/no questions. She takes her seat in the examination hall and stares at the questions for five minutes. Then, in a fit of inspiration, she takes her purse out, removes a coin, and starts tossing the coin and marking the answer sheet "yes" for heads and "no" for tails. Within a half an hour, she is all done, whereas the rest of the class is sweating it out.

During the last few minutes, she is seen desperately throwing the coin, swearing and sweating. The moderator, alarmed, approaches her and asks what is going on.

"I finished the exam in a half an hour," she says, "but I am rechecking my answers."