A blonde reports for his University's final examination that consists of Y/N type questions

A blonde reports for his university's final examination
That consists of y/n type questions.

He takes his seat in the examination hall,
Stares at the question paper for five minutes,
And then in a fit of inspiration takes his wallet out,
Removes a coin
And starts tossing the coin
and marking the answer sheet,
Y for heads
And n for tails.

Within half an hour he is all done
Whereas the rest of the class is sweating
It out. during the last few minutes,
He is seen desperately throwing the coin,
Swearing and sweating.

The moderator, alarmed,
Approaches him
And asks what is going on.

I finished the exam in half an hour.
But," he says,
"i'm not going to finish rechecking my answers!"