A martial arts class during which one student is holding a board broken by another student while others watch .
There is a better than even chance that a boy quickly breaks a plank to the amusement of the crowd .
There is a better than even chance that a boy quickly breaks a plank to the amusement of the crowd .
It is impossible that a boy quickly breaks a plank to the amusement of the crowd .
A boy quickly breaks a plank to the amusement of the crowd .