probability in the casino
$begingroup$
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.
probability
$endgroup$
add a comment |
$begingroup$
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.
probability
$endgroup$
$begingroup$
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
add a comment |
$begingroup$
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.
probability
$endgroup$
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
probability
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
add a comment |
$begingroup$
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
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
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.
$endgroup$
add a comment |
$begingroup$
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}$
$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
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
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active
oldest
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$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.
$endgroup$
add a comment |
$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.
$endgroup$
add a comment |
$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.
$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.
answered Mar 11 '14 at 13:32
Ross MillikanRoss Millikan
297k23198371
297k23198371
add a comment |
add a comment |
$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: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$
$endgroup$
$begingroup$
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
add a comment |
$begingroup$
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$$, and a chance of $1-frac{1}{2}^{40}$ to win 1$, which means that if you repeated the full game forever (restocking to be able to play 40 rounds again), you would neither gain money nor lose money, because $frac{1}{2}^{40}times (2^{40}-1) = (1-frac{1}{2}^{40})times 1$, as worked out below:
Lose: $frac{1}{2}^{40}times (2^{40}-1) = frac{1}{2}^{40}times 2^{40} - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$
Win: $(1-frac{1}{2}^{40})times 1 = 1-frac{1}{2}^{40}$
Lose = Win: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$
$endgroup$
$begingroup$
A careful reading of the Question will show you that winning (making a profit) does not depend on getting $40$ reds in a row.
$endgroup$
– hardmath
Apr 18 '18 at 16:25
$begingroup$
@hardmath Oops, thanks for pointing that out, I had given the probability of losing instead of that of winning.
$endgroup$
– alvitawa
Apr 19 '18 at 19:43
add a comment |
$begingroup$
The probability of you losing after an entire game is $frac{1}{2}^{40}$, because you have to get 40 reds in a row to lose, and the probability of getting a red is $frac{1}{2}$. The probability of making a profit is then $1-frac{1}{2}^{40}$.
Starting with 1$, the (maximum) amount of money you could lose after an entire game is $2^{40}-1$(lost 1$ after round one, 3$ after round two, 7$ after round three...), if you win once, you earn 1$. So playing this game you have a chance of $frac{1}{2}^{40}$ to lose $2^{40}-1$$, 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: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$
$endgroup$
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: $1 - frac{1}{2}^{40} = 1 - frac{1}{2}^{40}$
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
add a comment |
$begingroup$
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
add a comment |
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$begingroup$
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