Lil's Dead Giveaway Trick!

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!

EXAMPLE GAME

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!

HOW DOES IT WORK?

Look at what happened in the example after the first two cards. The customer won one and lost one, but instead of ending with his 100 back, he was already down to 75. If the two cards had appeared the other way round he would have first lost (100 - 50 = 50) and then won (50 + 25 = 75) and still have finished with 75.

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)4 = 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