This should be right up your alley, MathBabe. It's just math.
For fun, deal out two cards to you (AsKs) and two cards to me (7h8d)... Now deal out a 5 card board and see who wins. Now deal out another 5 card board and see who wins. And then another. And another. And another. Repeat untl you've dealt out EVERY possible combination, keep track of who wins along the way, and you'll have your answer.
You may want to use a computer to help out with this task
Alternatively, you could understand that this sort of thing has been done before, these numbers are proven, and you can just commit them to memory.