Martin,


We have about 0.1% of the information we need to give a precise mathematical answer :-).


It would be better to explain how this works so you can do your own calculations. What you need to do is count card combinations. For example, if someone reraises you and you know he will only reraise with AA, KK, QQ or AK then what is the probability that he has AA ? There are 6 AA hands he can have - AsAh, AsAc, AsAd, AhAd, AhAc, AcAd. Likewise 6 KK and 6 QQ, and 16 AK (many more because now the suits can be duplicated, plus AsKc is not the same hand as KsAc). So there are 34 hands he can have, 6 of them are AA and the probability of his having Aces is 6/34 = about 18%. But this is only as accurate as your "knowledge" of his re-raising hands.


Now, that is if you have say JJ. What if you have AK ? Now you remove the combinations which are blocked by your cards, there are 3 AA hands he could have, 3 KK, 6 QQ and 9 AK (check those numbers yourself !). Now the probability of AA is 3/21 = about 14%.


So what you have to do is perform this kind of calculation over the whole range of limping hands he could have, and this range is the necessary information which is missing for us to give you an answer. If he limps with any 2 cards, there are 1326 hands (52 x 51 / 2) he could have and so the probability of Aces is 6/1326 = about 1/220 which is where the figure quoted above comes from.


Hope this helps,


Andy.