probability in the casino












2












$begingroup$


I have a question regarding probability.



Lets assume that roulette has just red and black, no green and an equal amount of both.



Lets also assume we start each game with a bet of 1 dollar.
We also have enough dollars to be able to double our bet up to 40 times.



Now an example game is we bet our 1 dollar on black.
If we lose we bet 2 dollars on black, the total expenditure is now 3 dollars.
If we lose again we bet 4 dollars on black, the total expenditure is now 7 dollars.



If we win we get 8 dollars back. 1 of which is a profit.



Remember we can lose 40 times in a row before we cannot double up any longer.



The odds of getting 2 reds in a row is 25% so getting 40 reds in a row would be very low.



My question is what is the probability of making a profit after one entire game ( a game is where you keep doubling until you can or you profit)



and after 1000 games.










share|cite|improve this question









$endgroup$












  • $begingroup$
    Just remember before setting off to the casino with your doubling scheme that although you will win a little very often, when you loose you loose a LOT. Your expected return is still 0 on your even roulette wheel, and still negative on a wheel with one or two zeroes.
    $endgroup$
    – Tom Collinge
    Mar 11 '14 at 14:33






  • 2




    $begingroup$
    In practice this strategy is foiled by casino bet limits.
    $endgroup$
    – MJD
    Mar 11 '14 at 14:51












  • $begingroup$
    Congratulations, you just discovered the en.wikipedia.org/wiki/Martingale_(betting_system) While it will win in the long run, if there are no zer0s, it will win you only one betting unit. E.g. you will lose 1 + 2 + 4 + 8 (= 15) to win 16, or lose 31 to win 32, etc
    $endgroup$
    – Mawg
    Jan 11 '16 at 14:14
















2












$begingroup$


I have a question regarding probability.



Lets assume that roulette has just red and black, no green and an equal amount of both.



Lets also assume we start each game with a bet of 1 dollar.
We also have enough dollars to be able to double our bet up to 40 times.



Now an example game is we bet our 1 dollar on black.
If we lose we bet 2 dollars on black, the total expenditure is now 3 dollars.
If we lose again we bet 4 dollars on black, the total expenditure is now 7 dollars.



If we win we get 8 dollars back. 1 of which is a profit.



Remember we can lose 40 times in a row before we cannot double up any longer.



The odds of getting 2 reds in a row is 25% so getting 40 reds in a row would be very low.



My question is what is the probability of making a profit after one entire game ( a game is where you keep doubling until you can or you profit)



and after 1000 games.










share|cite|improve this question









$endgroup$












  • $begingroup$
    Just remember before setting off to the casino with your doubling scheme that although you will win a little very often, when you loose you loose a LOT. Your expected return is still 0 on your even roulette wheel, and still negative on a wheel with one or two zeroes.
    $endgroup$
    – Tom Collinge
    Mar 11 '14 at 14:33






  • 2




    $begingroup$
    In practice this strategy is foiled by casino bet limits.
    $endgroup$
    – MJD
    Mar 11 '14 at 14:51












  • $begingroup$
    Congratulations, you just discovered the en.wikipedia.org/wiki/Martingale_(betting_system) While it will win in the long run, if there are no zer0s, it will win you only one betting unit. E.g. you will lose 1 + 2 + 4 + 8 (= 15) to win 16, or lose 31 to win 32, etc
    $endgroup$
    – Mawg
    Jan 11 '16 at 14:14














2












2








2





$begingroup$


I have a question regarding probability.



Lets assume that roulette has just red and black, no green and an equal amount of both.



Lets also assume we start each game with a bet of 1 dollar.
We also have enough dollars to be able to double our bet up to 40 times.



Now an example game is we bet our 1 dollar on black.
If we lose we bet 2 dollars on black, the total expenditure is now 3 dollars.
If we lose again we bet 4 dollars on black, the total expenditure is now 7 dollars.



If we win we get 8 dollars back. 1 of which is a profit.



Remember we can lose 40 times in a row before we cannot double up any longer.



The odds of getting 2 reds in a row is 25% so getting 40 reds in a row would be very low.



My question is what is the probability of making a profit after one entire game ( a game is where you keep doubling until you can or you profit)



and after 1000 games.










share|cite|improve this question









$endgroup$




I have a question regarding probability.



Lets assume that roulette has just red and black, no green and an equal amount of both.



Lets also assume we start each game with a bet of 1 dollar.
We also have enough dollars to be able to double our bet up to 40 times.



Now an example game is we bet our 1 dollar on black.
If we lose we bet 2 dollars on black, the total expenditure is now 3 dollars.
If we lose again we bet 4 dollars on black, the total expenditure is now 7 dollars.



If we win we get 8 dollars back. 1 of which is a profit.



Remember we can lose 40 times in a row before we cannot double up any longer.



The odds of getting 2 reds in a row is 25% so getting 40 reds in a row would be very low.



My question is what is the probability of making a profit after one entire game ( a game is where you keep doubling until you can or you profit)



and after 1000 games.







probability






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Mar 11 '14 at 13:26









user134679user134679

111




111












  • $begingroup$
    Just remember before setting off to the casino with your doubling scheme that although you will win a little very often, when you loose you loose a LOT. Your expected return is still 0 on your even roulette wheel, and still negative on a wheel with one or two zeroes.
    $endgroup$
    – Tom Collinge
    Mar 11 '14 at 14:33






  • 2




    $begingroup$
    In practice this strategy is foiled by casino bet limits.
    $endgroup$
    – MJD
    Mar 11 '14 at 14:51












  • $begingroup$
    Congratulations, you just discovered the en.wikipedia.org/wiki/Martingale_(betting_system) While it will win in the long run, if there are no zer0s, it will win you only one betting unit. E.g. you will lose 1 + 2 + 4 + 8 (= 15) to win 16, or lose 31 to win 32, etc
    $endgroup$
    – Mawg
    Jan 11 '16 at 14:14


















  • $begingroup$
    Just remember before setting off to the casino with your doubling scheme that although you will win a little very often, when you loose you loose a LOT. Your expected return is still 0 on your even roulette wheel, and still negative on a wheel with one or two zeroes.
    $endgroup$
    – Tom Collinge
    Mar 11 '14 at 14:33






  • 2




    $begingroup$
    In practice this strategy is foiled by casino bet limits.
    $endgroup$
    – MJD
    Mar 11 '14 at 14:51












  • $begingroup$
    Congratulations, you just discovered the en.wikipedia.org/wiki/Martingale_(betting_system) While it will win in the long run, if there are no zer0s, it will win you only one betting unit. E.g. you will lose 1 + 2 + 4 + 8 (= 15) to win 16, or lose 31 to win 32, etc
    $endgroup$
    – Mawg
    Jan 11 '16 at 14:14
















$begingroup$
Just remember before setting off to the casino with your doubling scheme that although you will win a little very often, when you loose you loose a LOT. Your expected return is still 0 on your even roulette wheel, and still negative on a wheel with one or two zeroes.
$endgroup$
– Tom Collinge
Mar 11 '14 at 14:33




$begingroup$
Just remember before setting off to the casino with your doubling scheme that although you will win a little very often, when you loose you loose a LOT. Your expected return is still 0 on your even roulette wheel, and still negative on a wheel with one or two zeroes.
$endgroup$
– Tom Collinge
Mar 11 '14 at 14:33




2




2




$begingroup$
In practice this strategy is foiled by casino bet limits.
$endgroup$
– MJD
Mar 11 '14 at 14:51






$begingroup$
In practice this strategy is foiled by casino bet limits.
$endgroup$
– MJD
Mar 11 '14 at 14:51














$begingroup$
Congratulations, you just discovered the en.wikipedia.org/wiki/Martingale_(betting_system) While it will win in the long run, if there are no zer0s, it will win you only one betting unit. E.g. you will lose 1 + 2 + 4 + 8 (= 15) to win 16, or lose 31 to win 32, etc
$endgroup$
– Mawg
Jan 11 '16 at 14:14




$begingroup$
Congratulations, you just discovered the en.wikipedia.org/wiki/Martingale_(betting_system) While it will win in the long run, if there are no zer0s, it will win you only one betting unit. E.g. you will lose 1 + 2 + 4 + 8 (= 15) to win 16, or lose 31 to win 32, etc
$endgroup$
– Mawg
Jan 11 '16 at 14:14










2 Answers
2






active

oldest

votes


















2












$begingroup$

After one game, you make a dollar unless you lose $40$ times in a row, which happens $2^{-40}$ of the time, about once in $10^{12}$ tries. After $1000$ games, you have to win them all, so you will lose approximately $1000 cdot 2^{-40}$ of the time, or about once in a billion tries. This is not exact-it is actually smaller because some of the probability comes from two losses. The chance of that is greater than zero, but very small.






share|cite|improve this answer









$endgroup$





















    -2












    $begingroup$

    The probability of you losing after an entire game is $frac{1}{2}^{40}$, because you have to get 40 reds in a row to lose, and the probability of getting a red is $frac{1}{2}$. The probability of making a profit is then $1-frac{1}{2}^{40}$.



    Starting with 1$, the (maximum) amount of money you could lose after an entire game is $2^{40}-1$(lost 1$ after round one, 3$ after round two, 7$ after round three...), if you win once, you earn 1$. So playing this game you have a chance of $frac{1}{2}^{40}$ to lose $2^{40}-1$$, and a chance of $1-frac{1}{2}^{40}$ to win 1$, which means that if you repeated the full game forever (restocking to be able to play 40 rounds again), you would neither gain money nor lose money, because $frac{1}{2}^{40}times (2^{40}-1) = (1-frac{1}{2}^{40})times 1$, as worked out below:



    Lose: $frac{1}{2}^{40}times (2^{40}-1) = frac{1}{2}^{40}times 2^{40} - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$



    Win: $(1-frac{1}{2}^{40})times 1 = 1-frac{1}{2}^{40}$



    Lose = Win: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$






    share|cite|improve this answer











    $endgroup$













    • $begingroup$
      A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
      $endgroup$
      – hardmath
      Apr 18 '18 at 16:25










    • $begingroup$
      @hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
      $endgroup$
      – alvitawa
      Apr 19 '18 at 19:43











    Your Answer





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    2 Answers
    2






    active

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    2 Answers
    2






    active

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    active

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    active

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    2












    $begingroup$

    After one game, you make a dollar unless you lose $40$ times in a row, which happens $2^{-40}$ of the time, about once in $10^{12}$ tries. After $1000$ games, you have to win them all, so you will lose approximately $1000 cdot 2^{-40}$ of the time, or about once in a billion tries. This is not exact-it is actually smaller because some of the probability comes from two losses. The chance of that is greater than zero, but very small.






    share|cite|improve this answer









    $endgroup$


















      2












      $begingroup$

      After one game, you make a dollar unless you lose $40$ times in a row, which happens $2^{-40}$ of the time, about once in $10^{12}$ tries. After $1000$ games, you have to win them all, so you will lose approximately $1000 cdot 2^{-40}$ of the time, or about once in a billion tries. This is not exact-it is actually smaller because some of the probability comes from two losses. The chance of that is greater than zero, but very small.






      share|cite|improve this answer









      $endgroup$
















        2












        2








        2





        $begingroup$

        After one game, you make a dollar unless you lose $40$ times in a row, which happens $2^{-40}$ of the time, about once in $10^{12}$ tries. After $1000$ games, you have to win them all, so you will lose approximately $1000 cdot 2^{-40}$ of the time, or about once in a billion tries. This is not exact-it is actually smaller because some of the probability comes from two losses. The chance of that is greater than zero, but very small.






        share|cite|improve this answer









        $endgroup$



        After one game, you make a dollar unless you lose $40$ times in a row, which happens $2^{-40}$ of the time, about once in $10^{12}$ tries. After $1000$ games, you have to win them all, so you will lose approximately $1000 cdot 2^{-40}$ of the time, or about once in a billion tries. This is not exact-it is actually smaller because some of the probability comes from two losses. The chance of that is greater than zero, but very small.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Mar 11 '14 at 13:32









        Ross MillikanRoss Millikan

        297k23198371




        297k23198371























            -2












            $begingroup$

            The probability of you losing after an entire game is $frac{1}{2}^{40}$, because you have to get 40 reds in a row to lose, and the probability of getting a red is $frac{1}{2}$. The probability of making a profit is then $1-frac{1}{2}^{40}$.



            Starting with 1$, the (maximum) amount of money you could lose after an entire game is $2^{40}-1$(lost 1$ after round one, 3$ after round two, 7$ after round three...), if you win once, you earn 1$. So playing this game you have a chance of $frac{1}{2}^{40}$ to lose $2^{40}-1$$, and a chance of $1-frac{1}{2}^{40}$ to win 1$, which means that if you repeated the full game forever (restocking to be able to play 40 rounds again), you would neither gain money nor lose money, because $frac{1}{2}^{40}times (2^{40}-1) = (1-frac{1}{2}^{40})times 1$, as worked out below:



            Lose: $frac{1}{2}^{40}times (2^{40}-1) = frac{1}{2}^{40}times 2^{40} - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$



            Win: $(1-frac{1}{2}^{40})times 1 = 1-frac{1}{2}^{40}$



            Lose = Win: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$






            share|cite|improve this answer











            $endgroup$













            • $begingroup$
              A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
              $endgroup$
              – hardmath
              Apr 18 '18 at 16:25










            • $begingroup$
              @hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
              $endgroup$
              – alvitawa
              Apr 19 '18 at 19:43
















            -2












            $begingroup$

            The probability of you losing after an entire game is $frac{1}{2}^{40}$, because you have to get 40 reds in a row to lose, and the probability of getting a red is $frac{1}{2}$. The probability of making a profit is then $1-frac{1}{2}^{40}$.



            Starting with 1$, the (maximum) amount of money you could lose after an entire game is $2^{40}-1$(lost 1$ after round one, 3$ after round two, 7$ after round three...), if you win once, you earn 1$. So playing this game you have a chance of $frac{1}{2}^{40}$ to lose $2^{40}-1$$, and a chance of $1-frac{1}{2}^{40}$ to win 1$, which means that if you repeated the full game forever (restocking to be able to play 40 rounds again), you would neither gain money nor lose money, because $frac{1}{2}^{40}times (2^{40}-1) = (1-frac{1}{2}^{40})times 1$, as worked out below:



            Lose: $frac{1}{2}^{40}times (2^{40}-1) = frac{1}{2}^{40}times 2^{40} - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$



            Win: $(1-frac{1}{2}^{40})times 1 = 1-frac{1}{2}^{40}$



            Lose = Win: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$






            share|cite|improve this answer











            $endgroup$













            • $begingroup$
              A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
              $endgroup$
              – hardmath
              Apr 18 '18 at 16:25










            • $begingroup$
              @hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
              $endgroup$
              – alvitawa
              Apr 19 '18 at 19:43














            -2












            -2








            -2





            $begingroup$

            The probability of you losing after an entire game is $frac{1}{2}^{40}$, because you have to get 40 reds in a row to lose, and the probability of getting a red is $frac{1}{2}$. The probability of making a profit is then $1-frac{1}{2}^{40}$.



            Starting with 1$, the (maximum) amount of money you could lose after an entire game is $2^{40}-1$(lost 1$ after round one, 3$ after round two, 7$ after round three...), if you win once, you earn 1$. So playing this game you have a chance of $frac{1}{2}^{40}$ to lose $2^{40}-1$$, and a chance of $1-frac{1}{2}^{40}$ to win 1$, which means that if you repeated the full game forever (restocking to be able to play 40 rounds again), you would neither gain money nor lose money, because $frac{1}{2}^{40}times (2^{40}-1) = (1-frac{1}{2}^{40})times 1$, as worked out below:



            Lose: $frac{1}{2}^{40}times (2^{40}-1) = frac{1}{2}^{40}times 2^{40} - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$



            Win: $(1-frac{1}{2}^{40})times 1 = 1-frac{1}{2}^{40}$



            Lose = Win: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$






            share|cite|improve this answer











            $endgroup$



            The probability of you losing after an entire game is $frac{1}{2}^{40}$, because you have to get 40 reds in a row to lose, and the probability of getting a red is $frac{1}{2}$. The probability of making a profit is then $1-frac{1}{2}^{40}$.



            Starting with 1$, the (maximum) amount of money you could lose after an entire game is $2^{40}-1$(lost 1$ after round one, 3$ after round two, 7$ after round three...), if you win once, you earn 1$. So playing this game you have a chance of $frac{1}{2}^{40}$ to lose $2^{40}-1$$, and a chance of $1-frac{1}{2}^{40}$ to win 1$, which means that if you repeated the full game forever (restocking to be able to play 40 rounds again), you would neither gain money nor lose money, because $frac{1}{2}^{40}times (2^{40}-1) = (1-frac{1}{2}^{40})times 1$, as worked out below:



            Lose: $frac{1}{2}^{40}times (2^{40}-1) = frac{1}{2}^{40}times 2^{40} - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$



            Win: $(1-frac{1}{2}^{40})times 1 = 1-frac{1}{2}^{40}$



            Lose = Win: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$







            share|cite|improve this answer














            share|cite|improve this answer



            share|cite|improve this answer








            edited Dec 22 '18 at 22:59

























            answered Apr 18 '18 at 15:51









            alvitawaalvitawa

            13




            13












            • $begingroup$
              A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
              $endgroup$
              – hardmath
              Apr 18 '18 at 16:25










            • $begingroup$
              @hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
              $endgroup$
              – alvitawa
              Apr 19 '18 at 19:43


















            • $begingroup$
              A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
              $endgroup$
              – hardmath
              Apr 18 '18 at 16:25










            • $begingroup$
              @hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
              $endgroup$
              – alvitawa
              Apr 19 '18 at 19:43
















            $begingroup$
            A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
            $endgroup$
            – hardmath
            Apr 18 '18 at 16:25




            $begingroup$
            A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
            $endgroup$
            – hardmath
            Apr 18 '18 at 16:25












            $begingroup$
            @hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
            $endgroup$
            – alvitawa
            Apr 19 '18 at 19:43




            $begingroup$
            @hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
            $endgroup$
            – alvitawa
            Apr 19 '18 at 19:43


















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