how much hours to study one day before exam?

This is a wise decision. If you haven't studied enough before the last day, the last hours won't help you anyway. It's better to go to the exam relaxed.

Be sure to get enough sleep and eat a good breakfast to.

that is a good thing to do. they say a good night sleep with relax your brain and even help you remember what you have studied

Just revise your lessons for one hour on the day before your exam. Don't keep on revising and stress yourself.

I like pulling an all-nighter......I do last minute studies,though I know that it is not the best way to prepare for an examination and sleep is very essential for the brain to function efficiently I just can't help it as I am a good procrastinator.I just get bored seeing people who finish with their studies beforehand and do umpteen number of revisions......Reading the same thing over and over again....Is'nt it boring?.....LOL.....