Jill reported for her university final exam which consisted of "true/false" type questions. She took her seat in the examination hall, stared at the question paper for five minutes.
In a fit of inspiration, she took her purse out, removed a coin and started tossing the coin and marking the answer sheet: true for heads and false for tails.
Within thirty minutes she was all done, whereas the rest of the class was still working furiously.
During the last few minutes, she was seen desperately throwing the coin, swearing and sweating.
The moderator, alarmed, approached her and asked what is going on.
"I finished the exam in a half hour," she said. "Now I'm rechecking my answers."