Two Plus Two Older Archives  

Go Back   Two Plus Two Older Archives > General Gambling > Probability
FAQ Community Calendar Today's Posts Search

Reply
 
Thread Tools Display Modes
  #1  
Old 03-24-2005, 07:14 PM
chipbrave chipbrave is offline
Junior Member
 
Join Date: Jun 2004
Posts: 7
Default What are the odds of 2 people flopping a flushin Hold\'em?

What are the odds of 2 people flopping a flushin Hold'em? it keeps happening w/me unfortunately being on the short end. Just curious.
Thanks
Reply With Quote
  #2  
Old 03-24-2005, 08:33 PM
pzhon pzhon is offline
Member
 
Join Date: Mar 2004
Posts: 66
Default Re: What are the odds of 2 people flopping a flushin Hold\'em?

The probability of a monotone flop is 22/425 ~ 5.1764%.

Given that there is a monotone flop, the following is the distribution of the number of people with flushes (or straight-flushes, henceforth counted as flushes):

0 66.017%
1 29.877%
2 3.932%
3 0.172%
4 0.002%
5 0.000003%

Given that you flop a flush (~ 1/505) the following is the distribution of the number of people with flushes, including you:

1 78.079% (no other flopped flushes)
2 20.552%
3 1.347%
4 0.022%
5 0.00004%

The probability that you flop a flush is about 1/505. The probability at least one person flops a flush is about 1/56.8, so the probability that you flop a flush that is high is about 1/568. 1/505-1/568 ~ 1/4511 of the time, you flop a flush that is not high.
Reply With Quote
  #3  
Old 03-24-2005, 08:43 PM
gaming_mouse gaming_mouse is offline
Senior Member
 
Join Date: Oct 2004
Location: my hero is sfer
Posts: 2,480
Default Re: What are the odds of 2 people flopping a flushin Hold\'em?

[ QUOTE ]
The probability of a monotone flop is 22/425 ~ 5.1764%.

Given that there is a monotone flop, the following is the distribution of the number of people with flushes (or straight-flushes, henceforth counted as flushes):

0 66.017%
1 29.877%
2 3.932%
3 0.172%
4 0.002%
5 0.000003%

Given that you flop a flush (~ 1/505) the following is the distribution of the number of people with flushes, including you:

1 78.079% (no other flopped flushes)
2 20.552%
3 1.347%
4 0.022%
5 0.00004%

The probability that you flop a flush is about 1/505. The probability at least one person flops a flush is about 1/56.8, so the probability that you flop a flush that is high is about 1/568. 1/505-1/568 ~ 1/4511 of the time, you flop a flush that is not high.

[/ QUOTE ]

nice answer, pzhon. i'm just going to point out that i believed you assumed random cards on the part of your opponent. this offers a useful baseline estimate, but more accurate approximations can be obtained by assuming more reasonable starting hand selection.
Reply With Quote
  #4  
Old 03-25-2005, 03:32 AM
gamble4pro gamble4pro is offline
Member
 
Join Date: Nov 2004
Posts: 39
Default Re: What are the odds of 2 people flopping a flushin Hold\'em?

This calculation is made from outside view (by not taking into account own hole cards).
The flop is suited.
The odds of one player (a specific one) to hold two cards of that suit are C(10,2)/C(49,2) = 45/1176= 3.826%.
The odds of two players (two specific players) to hold two cards of same suit are C(10,2)*C(8,2)/(C(49,2)*C(47,2))= 0.099%.
If you want the odds of two players (any) to hold that suit you have to multiply 0.099% by C(n,2)= n*(n-1)/2, where n is the number of players.
If you want the odds for at least two players to hold that suit, the formula is much more heavy (maximum 5 players could simultaneously hold that suit).
Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:39 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.