kk v aa question

[Dommer]

I made myself look like an idiot early arguing with a friend so I'm hoping someone here can clarify a question for me.

If you hold KK, and someone goes all-in so that you are getting basically 1-1 on your call (ignoring blinds, pretend stacks are big, 100 bb or so), what % of the time do they need to hold AA for it to be an unprofitable call for you?

I guess you need to know what other hands he will have if he doesn't have AA, for simplicity sake lets pretend its any other pair. If you wanted to get more complex you could add in AK, AQ, AJ, etc.

So how would I go about solving this?

Thanks much,
Tom

[pzhon]

[ QUOTE ]

If you hold KK, and someone goes all-in so that you are getting basically 1-1 on your call (ignoring blinds, pretend stacks are big, 100 bb or so), what % of the time do they need to hold AA for it to be an unprofitable call for you?

I guess you need to know what other hands he will have if he doesn't have AA, for simplicity sake lets pretend its any other pair.

[/ QUOTE ]
It's close to 50%.

According to PokerStove (http://www.pokerstove.com), KK wins 18.054% of the pot against AA, which means KK expects to lose 63.9% of a stack. KK expects to win 80.613% against the range 22-KK, or 61.2% of a stack. So, you need to be at least a 63.9:61.2 favorite to be up against a hand other than AA in order to call. The probability has to be at least 61.2/(61.2+63.9)= 48.9% that you are up against AA to fold.

Some people think that just because it is unlikely a priori that your opponent has AA, you must be close to 100% convinced that your opponent has AA to fold. This is wrong by a lot. In practice, there is often a lot of dead money in the pot when your opponent represents AA, and you often should fold even if you only think you are up against AA 60% of the time. It's worse if not all of the money is in: you might have to fold if there is less than a 50% chance your opponent has AA.