Results 1 to 1 of 1

Math Help - Doubling a roulette bet

  1. #1
    Junior Member
    Joined
    Jun 2011
    Posts
    45

    Doubling a roulette bet

    A very simple question has me very confused..

    Assume that a roulette table has 38 numbers 0, 00, 1, 2 ..., 35, 36. 0 & 00 are green, and the remaining numbers are split evenly between red and black. If a player bets black, the odds of winning and doubling his money is 18/38 = 0.473%.

    Consider the following strategy. The player initially bets $2 on black. On each turn, if the player wins, he stops playing. If the player loses, he doubles his bet and keeps playing. Calculate the expected value of the the player's earnings.

    E[Game] = E[First Turn] + E[Second Turn] + ... + E[nth Turn] = [2(0.473) - 2(.527)] + [4(0.473) - 4(.527)] + ... = some negative number

    Now, assume that the roulette table has 38 numbers evenly split between red and black. How does this affect the expected earnings?

    I would have assumed that you are expected to break even.. but when I think about it, I don't understand why you have not doubled your initial bet by the end. It seems inevitable that black will eventually hit, and if you double your bet each time, then when you decide to finish, you will have only lost $2 less than you won...

    Can someone help me work through this conceptually?
    Last edited by jsndacruz; May 25th 2012 at 02:05 PM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. doubling time
    Posted in the Calculus Forum
    Replies: 3
    Last Post: August 16th 2009, 08:20 AM
  2. Bacteria doubling
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 8th 2009, 05:37 PM
  3. Doubling time
    Posted in the Calculus Forum
    Replies: 1
    Last Post: May 2nd 2009, 06:37 PM
  4. doubling time
    Posted in the Algebra Forum
    Replies: 1
    Last Post: January 26th 2009, 10:46 PM
  5. doubling
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: May 18th 2007, 03:40 PM

Search Tags


/mathhelpforum @mathhelpforum