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Can someone tell me if these odds are worth...
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You are currently reading a thread in /sci/ - Science & Math

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Can someone tell me if these odds are worth playing? I have a friend who says, theoretically, I can always do this with him.

Pay him 25 cents to play.

Then I get to roll 3 dice.

If I get a 3, he gives me $10. There is a 1/216 or .5% chance of getting this.

If I get a 7, I get my quarter back. There is a 15/216 or 7% chance of getting this.

I get a 13, I get $2. There is a 9.7% chance of getting this.

I get an 18, I get $5. There is 1/216 or a .5% chance of getting this.

Wouldn't the dealer end up losing with these odds? Especially with the 13, at 9.7 paying $2. Also, 25 cents for a .5% chance to win $10 doesn't seem like good house odds to me, but I don't know about this stuff. I suspect he doesn't either.
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I'm a girl btw ;)
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>>7762678
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Simple probability,
[math] expected winnings ($) = \Sigma (probabilities \times winnings) - $0.25[/math]
So your expected winnings is
[math] $10 \times \frac {1}{216} + $0.25 \times \frac {15}{216} + $2 \times \frac {21}{216} + $5 \times \frac{1}{216} - $0.25 [/math]
or $0.03125.

So technically you win 3 cents per round.
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>>7762645
Lets say you play 200 games.

You win at 1 of the 10$

You win 14 of the quarter back so you get 3.5$

You win 20 of the 2$ so you get 40$

You win one of the 5$ so 5$

That totals 58.5$

You wasted 50$ so you win 8.50$

But the big difference here are the 5$ and 10$ rolls.

I chose 200 because below that, there is not even a 1% of winning the 5$ or 10$ so you could not even win it once (statistically). And if you don't roll them, specially the 10, you will lose money.

In other words, you only play when you are allowed to roll the dices >200 times.
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>>7762706
>>7762701

I see. So my friend is a dumbass.
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>>7762723
Technically yes, but this only works out in the long run, so in a short amount of trials you would come up negative
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>>7762701
I know I sound stupid for asking this, but I have a problem with the probability of something happening and am generally wondering what is the best things to learn so I can figure it out myself. Thanks.
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>>7762816
Khan Academy is always good, or you can get some of the /sci/ approved text books if videos aren't your thing
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>>7762822
Well I mean should I learn statistics? Is there a term for it or simply called probability math?
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>>7762827
you don't have to learn statistics, but its a good thing to know, and it ties in nicely to probability. I have no clue if theres an official term, I've only heard it referred to as probability.
Thread replies: 11
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