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Sins of the Gambler 2 (Posted on 2007-04-05) Difficulty: 4 of 5
A gambler playing roulette has a superstition that he must place bets for exactly 10 spins of a roulette wheel (American wheel with 00). He has a bankroll of $300 and the table limits are minimum $1 and maximum $150, with $1 increments.

Can you find a strategy which guarantees he will be able to place ten bets and will have at least a 96% chance of making a profit (finishing bankroll of at least $301)?

  Submitted by Brian Smith    
Rating: 5.0000 (1 votes)
Solution: (Hide)
The gambler should stick to making only even money bets. For the first five bets, he should place bets of $10, $19, $37, $73, and $145 if he does not have any wins up to that point. As soon as he wins on any the first five bets, then all the remaining bets are $1.

If he loses all first five bets, then he will have only $16. For the next 4 bets, he should place bets of $12, $25, $51, and $103, if he keeps winning in the last five bets. As soon as he loses on any of those four bets, he will have just enough to bet $1 on each of the remaining bets.

If in the extreme case of losing the first five and winning the next four, he should make his last bet $94 or greater to have a chance of getting at least $301.

His chances of failing are (10/19)^5 * (1 - (9/19)^5) = .039423 = 3.9423%, which makes his chance of success 96.0573%

Comments: ( You must be logged in to post comments.)
  Subject Author Date
re(2): Solutionhoodat2007-04-05 20:57:02
re: Solution (for the alternate case)Gamer2007-04-05 17:58:07
re: SolutionCharlie2007-04-05 15:08:24
SolutionSolutionhoodat2007-04-05 14:41:28
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