AA?

[therockofgibraltar]

I raise preflop. Everybody folds to a player who reraises me. I cap with my AK.

Me and one opponent see the flop.
A-6-4 rainbow
I bet-he raises-I reraise-he caps.

turn is 8.
i bet - he raises - i went into calling mode and finally won the pot, he had A9s.

BUT the question ain't related to my "bad" play. It is a probability question. If I have AK and the flop contains one A, what is the chances that my opponent has AA??