four 7s before a 10
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July 6th, 2017 at 6:28:24 AM
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I liked to think I was good at math and stats until I found the wizard's site. Kudos, this place is awesome. Question: How can I construct the equation to figure the odds of getting four 7s before I see a 10 (for the intention of a parlay). The 7s don't have to be in order, just before the 10 appears. Thanks
July 6th, 2017 at 6:59:29 AM
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I assume you're talking about dice. (2/3) ^ 4 ~ 19.8% chance of rolling four 7s before a 10.
July 6th, 2017 at 7:00:32 AM
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Hi twobluecats, and welcome to the forums.
You need to give us a bit more info. Are you saying drawing 1 card at a time in a standard 52 card deck? Are you talking about throwing fair craps dice? Are you referring to some other game/rules/etc?
You need to give us a bit more info. Are you saying drawing 1 card at a time in a standard 52 card deck? Are you talking about throwing fair craps dice? Are you referring to some other game/rules/etc?
Playing it correctly means you've already won.
July 6th, 2017 at 7:00:36 AM
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I figured it'd be approximately 20%, though I can't show my math. Yes, dice.
July 6th, 2017 at 8:54:59 AM
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Quote: twobluecatsI figured it'd be approximately 20%, though I can't show my math. Yes, dice.
Here's a breakdown of the probabilities of various numbers of 7s before a 10:
0: 33.3%
1: 22.2%
2: 14.8%
3: 9.9%
So, the probability of having three or fewer 7s before a 10 is 33.3% + 22.2% + 14.8% + 9.9% = 80.2%. And that equates to a probability of 19.8% of four or more 7s before a 10. And that's very close to your 20% answer and Ace's.
July 6th, 2017 at 8:56:10 AM
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Odds of seeing a 10 are 3/36. Odds of seeing 1 seven is 6/36. All other rows are independent.
Odds of seeing one 7 before a 10 is 2/3. Odds of seeing 4 7s before a 10 is (2/3)^4 = 19.7531%
to elaborate on Chester:
0 7s = 1-2/3 = 33.33%
1 7 = 2/3 = 66.67%
2 7s = (2/3)^2 = 44.44%
3 7s = (2/3)^3 = 29.63%
4 7 = (2/3) ^ 4 = 19.75%
Dice have no memory.
Odds of seeing one 7 before a 10 is 2/3. Odds of seeing 4 7s before a 10 is (2/3)^4 = 19.7531%
to elaborate on Chester:
0 7s = 1-2/3 = 33.33%
1 7 = 2/3 = 66.67%
2 7s = (2/3)^2 = 44.44%
3 7s = (2/3)^3 = 29.63%
4 7 = (2/3) ^ 4 = 19.75%
Dice have no memory.
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You want the truth! You can't handle the truth!
July 6th, 2017 at 9:07:43 AM
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Quote: boymimbo
Dice have no memory.
You got that right. Thx everyone.
July 6th, 2017 at 11:29:48 AM
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do tell the way you would parlay a 10
(why not the 4?)
I mean, how much bet, do you work on the come out roll
that kind of stuff
*****
this is also easily simulated too (in like WinCraps Classic)
19,836 out of 100,000 10s there were
at least
4 7s
before the 10
that is 19.8%
thank you for sharing
Sally
forgot to mention
I used actual dice rolls in the simulation
(why not the 4?)
I mean, how much bet, do you work on the come out roll
that kind of stuff
*****
this is also easily simulated too (in like WinCraps Classic)
19,836 out of 100,000 10s there were
at least
4 7s
before the 10
that is 19.8%
| # of 7s B4 a 10 | count |
|---|---|
| 0 | 33477 |
| 1 | 22321 |
| 2 | 14651 |
| 3 | 9715 |
| 4 | 6655 |
| 5 | 4440 |
| 6 | 2854 |
| 7 | 1958 |
| 8 | 1337 |
| 9 | 860 |
| 10 | 585 |
| 11 | 374 |
| 12 | 253 |
| 13 | 185 |
| 14 | 119 |
| 15 | 57 |
| 16 | 51 |
| 17 | 39 |
| 18 | 29 |
| 19 | 10 |
| 20 | 11 |
| 21 | 7 |
| 22 | 3 |
| 23 | 4 |
| 24 | 3 |
| 25 | 2 |
| total | 100000 |
thank you for sharing
Sally
forgot to mention
I used actual dice rolls in the simulation
I Heart Vi Hart
July 6th, 2017 at 1:56:18 PM
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the only reason to wait for any event until you parlay in Craps is to slow down your betting. You could immediately increase your bet instead of waiting and the chance of winning the bet is the same as when waiting for however many 7s to have been rolled first, or any other event.
You didn't say you thought otherwise, but it often is the reason a player is asking questions like that.
You didn't say you thought otherwise, but it often is the reason a player is asking questions like that.
the next time Dame Fortune toys with your heart, your soul and your wallet, raise your glass and praise her thus: “Thanks for nothing, you cold-hearted, evil, damnable, nefarious, low-life, malicious monster from Hell!” She is, after all, stone deaf. ... Arnold Snyder
