This is one of the many tricks that Riverboat Lil plays in the Last Chance Saloon to win money. It looks like a game that the customer cannot lose, but they always do!
Customer starts with £100 so he bets £50
CARD 1 = BLACK Customer wins! Total money = £100 + £50 = £150 |
Customer has £150 so he bets £75
CARD 2 = RED Customer loses! Total money = £150 - £75 =£75 |
Customer has £75 so he bets £37
CARD 3 = BLACK Customer wins! Total money = £75 + £37 = £112 |
Customer has £112 so he bets £56
CARD 4 = RED Customer loses! Total money = £112 - £56 = £56 |
Customer has £56 so he bets £28
CARD 5 = BLACK Customer wins! Total money = £56 + £28 = £84 |
Customer has £84 so he bets £42
CARD 6 = BLACK Customer wins! Total money = £84 + £42 = £126 |
Customer has £126 so he bets £63
CARD 7 = RED Customer loses! Total money = £126 - £63 = £63 |
The customer will always lose, regardless of what order the seven cards appear!
A BLACK card has the effect of multiplying the current total of money held by 3/2.
A RED card has the effect of multiplying the current total of money by 1/2.
The game offers four BLACKS and three REDS, so the final fraction of money left will be (3/2)^{4} x (1/2)^{3} = 81/128 = about 63%. So if the player starts with £100, he will only finish with about £63 regardless of what order the cards are picked.
If you like this then try The Red and Black Mystery!
This trick and many others appear in Brainbenders |
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Copyright (c) Kjartan Poskitt 2002