Another Odds Question

Discussion in 'Politics' started by TGregg, Dec 30, 2002.

  1. TGregg


    Here’s one that has fooled some pretty bright people (took me a while to understand it).

    Imagine that there is a game show with three doors in front of you (all are closed). Behind one door is the real prize and behind the other two are losers.

    You pick a door. The host opens a different door to show a booby prize (you knew before hand that the host would open a door to show a loser). This leaves two closed doors, the one you picked and another one. The host gives you an opportunity to switch doors. The question is, should you switch doors? What are the odds?

    It's my understanding that this was how Let's Make a Deal worked (a popular game show in the USA way back when).
  2. bobcathy1

    bobcathy1 Guest

    You can change or not. Your odds remain the same. Yes or No. 50/ me, the math deprived.
  3. TGregg


    Heh, that's what I thought at first. But the truth is that your odds if you stay with your original choice are 1 in 3, whereas your odds if you switch are 2 in 3. So you should switch.

    And this is my 100th post :D.
  4. nitro


    This is yet another variation on Restricted Choice, as in the "hats" thread (which I got on the wrong side of 1/3 :( )

  5. nitro


    100 posts!!!

    How did you get it so high?

  6. First, you use social engineering to get Monty to whisper in your ear what door to pick. If he doesn't bite, pull out a 9-millimeter and grab the person next to you in a headlock and put the gun to their head. Then tell Monty, "Homie don't want no goat!"

    Monty will then show you the correct door -- this method is 100% infallible.
  7. TGregg


    Should anybody believe that it's still 50-50 here's an experiment we can do where I will nearly always win. We'll use a billion doors in our experiment. The person who thinks it's even chances will be Monty, and pick one door between 1 and a billion (inclusive), then send that number to somebody who is neutral. Then, I'll pick a door and announce it here. Then, "Monty" will open all doors but two, where the door I picked is closed and the door that has the prize is closed. Should they be the same door, Monty will pick another door to be closed, so that there are two doors closed.

    Then I'll switch and win, unless I was (un?)lucky enough to pick the right door on my initial guess (a one in a billion chance).
  8. bobcathy1

    bobcathy1 Guest

    A quicker way is just to dump a hand grenade in his shorts with a long string. The personal touch.:D