Roulette Betting "System"
Date: 08/09/97 at 11:35:38 From: Connie Subject: Roulette betting "system" One roulette system is to bet $1 on black. If black comes up on the first spin of the wheel, you win $1 and the game is over. If black does not come up, double your bet ($2). If you win, your net winnings for two spins is still $1. Continue this doubling procedure until you eventually win; in every case your net winnings amount to $1. What is the fallacy with this betting "system"?
Date: 08/09/97 at 12:41:41 From: Doctor Anthony Subject: Re: Roulette betting "system" Consider how much 'doubling' your stake amounts to after a few turns. Your outgoings will be: 1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 + 256 + 512 + 1024 + (total is 2047 to here) + 2048 + 4096 + 8192 + 16384 + 32,768 + 65,536 + 131,072 + 262,144 + 524,288 + 1,048,576 + ... You need a very deep pocket to stand these losses. In theory you cover your losses by doubling, but in practice your nerve will crack long before your total wealth has gone down the tubes. Remember that at each stage you have an even chance of winning or losing. What happened on the last ten or more throws has no bearing on what happens next. If there were 20 reds in a row, the probability that the next throw would be red is still 1/2. -Doctor Anthony, The Math Forum Check out our web site! http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994-2015 The Math Forum