tommyngo215
tommyngo215
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July 28th, 2015 at 9:27:20 AM permalink
Hello,

Would somebody please show me how to calculate the probability of getting a 6 cards straight Flush in a 8 decks game? Similar to the 3 card poker's 6 card Bonus bet that I see all over Vegas..

Thanks,
Tommy
studmuffn
studmuffn
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July 28th, 2015 at 9:47:03 AM permalink
Not sure which game you're talking about, but I can do it for 6 cards off the top of an 8 deck shoe. Probability I got is 1 in 40,000.
Possible combinations: 416choose6 = 6.94e12 hands

Winning combinations: 9straights^8decks*4suits = 1.72e8

Probability: 1.72e8/6.94e12 = .000025 = 1 in 40,318
tommyngo215
tommyngo215
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July 28th, 2015 at 10:11:11 AM permalink
Thank you Studmuffn! that was quick haha I was still playing with this formula and then I got stuck. Perhaps, I did it completely wrong lol
(52/416)*(12/415)*(11/414)*(10/413)*(9/412)*(8/411) I was like ehhhhhh. Thanks for your quick reply again I really appreciate that.
SOOPOO
SOOPOO
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July 28th, 2015 at 11:09:05 AM permalink
Quote: tommyngo215

Thank you Studmuffn! that was quick haha I was still playing with this formula and then I got stuck. Perhaps, I did it completely wrong lol
(52/416)*(12/415)*(11/414)*(10/413)*(9/412)*(8/411) I was like ehhhhhh. Thanks for your quick reply again I really appreciate that.



It's not as simple as that. Since there is no 'wrap around' straight flush, the first card matters.... a deuce is less likely to produce a six card straight flush than a 7 as an example. (j, q, k, A, 2, 3) does not count as a 6 card straight flush)
miplet
miplet
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July 28th, 2015 at 11:22:09 AM permalink
Quote: studmuffn

Not sure which game you're talking about, but I can do it for 6 cards off the top of an 8 deck shoe. Probability I got is 1 in 40,000.

Possible combinations: 416choose6 = 6.94e12 hands

Winning combinations: 9straights^8decks*4suits = 1.72e8

Probability: 1.72e8/6.94e12 = .000025 = 1 in 40,318


Your winning combinations is off. It's 9*4*8^6 ( 9 straights * 4 suits * 8 cards for each of the 6 ranks)
“Man Babes” #AxelFabulous
studmuffn
studmuffn
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July 28th, 2015 at 12:48:56 PM permalink
Quote: miplet

Your winning combinations is off. It's 9*4*8^6 ( 9 straights * 4 suits * 8 cards for each of the 6 ranks)



Hm that's not how I see it. I stand by the exponent being the number of decks in the shoe because a low straight in spades could have n different AoS, 8 different deuces, etc.

The length of the straight (6) only factors into the combinatorial and the number of possible straights (here it can start with Ace thru 9). In your equation, a straight of 13 is more than certain.
CrystalMath
CrystalMath
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July 28th, 2015 at 5:34:19 PM permalink
Miplet is right.
I heart Crystal Math.
studmuffn
studmuffn
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July 29th, 2015 at 9:08:16 AM permalink
Ok, I think I understand. straights*suits*decks^ranks

That makes sense, thanks for the correction.

I guess that puts OPs probability even lower, down to 1 in 736,000
tommyngo215
tommyngo215
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July 29th, 2015 at 12:46:06 PM permalink
Thanks so much everybody for your replies.
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