Anyone know the odds? 2 pair flop clashes

BigBluster

Twice recently I've flopped top and bottom pair while a villain has flopped top two. One blind clash between A8s and A9s cost me a packet when the flop came A98.

Does anyone know the odds of this? Maybe it's far more common than I've guessed.

Thanks.

Bosschops

happens to me quite alot trust me its annoying lol

grantorino

Ok will have a go at this, could be way out. These are the odds he has 2 pair assuming you have flopped 2 pair

4 combos of same 2pair
6 each of different 2 pair give a total of 16 combos

He can hve any 2 of the 47 cards not seen=1081

16/1081~1.5%.

Also 5 combos of sets, if you are interested add on ~0.45%

I probably missed something here, also this is not probability before deal you both flop 2 pair, its I have 2 pair whats prob villain also has 2 pair.

I await the maths flaming

EDIT: This assumes he can have any 2 cards in his hand, so in reality probability he has 2 pair is higher especially on a board like A89 where all 2 pair combos are fairly likely, where as him having stuff like 25o is very unlikely 

BigBluster

Thanks - so it's about 2% mathematically.
But as you point out, the mathematics is not the end of it. If you have KQ on a AKQ flop, you're going to run into a higher 2-pair a lot more than 1 in 50, maybe as much as 1 in 10.

grantorino

Its more that as always with poker our information is imperfect. If we knew his exact range the maths works fine