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3rdEye
05-04-2004, 03:04 AM
As a random exercise to kill time, I decided to try to calculate the probability that, in hold'em, given that two players see a flop, one of which has a pocket pair and the other has an unpaired hand dominated by the other player (e.g., 88 vs. 87), both players will flop a boat. My statistics are rusty, so I wanted to see whether my calculations are correct.

Given my example, in which one player holds 87 vs. his opponent's 88, the flop necessary to satisfy my condition is 8 7 7. There are only 4 cards left in the deck that can make the necessary 3-card flop: the 1 remaining 8 and the 3 remaining 7's.

The probability of 3 of these 4 cards hitting on the flop, given 48 unseen cards, is: (4/48)*(3/47)*(2/46). Given these four cards, and letting the 3 remaining 7's be 7a, 7b, and 7c, respectively, there are four possible 3-card combinations: 7a 7b 7c, 8 7a 7b, 7a 8 7c, and 7a 7b 8. Thus the necessary flop will arise 3/4 times that 3 of the 4 necessary cards hit on the flop (i.e., when the flop isn't three 7's).

Thus, the probability that, given the aforementioned hands, both players will hit a boat on the flop is as follows: (4/48)*(3/47)*(2/46)*(3/4) = 72/415104 = 3/17296 ~ 1/5765 ~ 0.0001735, or 0.01735%.

I'm only posting this to see whether I'm calculating the probabilities correctly in the hopes that some of the posters here who have a better command of statistics than I will be courteous enough to respond.

Thanks in advance.

3rdEye
05-04-2004, 03:26 AM
Incidentally, this is the only way that two players can hit a boat on the flop.

Lost Wages
05-04-2004, 08:10 AM
If both players have a pocket pair and the flop is 3 of a rank then both players have made a full house.

Lost Wages

Lost Wages
05-04-2004, 08:19 AM
One player has 88 and and the other 87. There are 48 cards available for the flop leading to C(48,3)= (48*47*46)/6 = 17,296 possible flops.

There are 1*C(3,2) = 3 flops of 877.

3/17,296 = 0.01735%
So, yes you are correct.

Lost Wages

BigBiceps
05-04-2004, 02:30 PM
[ QUOTE ]
Incidentally, this is the only way that two players can hit a boat on the flop.

[/ QUOTE ]

There are two ways that two players can hit a full house on the flop of 8 7 7

88 vs 87
and
87 vs 87.

3rdEye
05-04-2004, 02:34 PM
True, Big Biceps. I feel like a moron for not seeing that.

3rdEye
05-04-2004, 02:35 PM
Also true...I should stop posting so early in the morning when I'm exhausted. /images/graemlins/smile.gif

Tater10
05-05-2004, 05:56 PM
This just happened to me at pokerplex. I had 83 in the bb and utg had 33. Flop 883.

Unlimited raises at pokerplex! If a 9 didn't hit the river, i'd still be betting.