After you choose a door, the host has to open one. Two out of the three times, he has no choice which one to open. When you pick the door at first, you have a 1/3 chance of being right. After he opens a door, if you stay with the door you first chose, you still have a 1/3 chance, if you switch, you have a 2/3 chance. There are three possibilities, considering you switch doors. 1) you were right at first, and you lose 2) you were wrong at first, and you win 3) you were wrong at first(other door), and you win Two out of the three possible outcomes, you win
It also might help if you think of 100 doors instead of 3. You choose one door, you have a 1/100 or 1% chance of being right. You stay with that door while the host opens 98 doors, so you are down to 2, the one you originally chose, and the last one that he hasn't open. Staying with your first choice, you still have a 1% chance. But if you switch, you have a 99% chance. There is a reason that he hasn't yet opened that door. By opening the other ones, he's giving you a clue about where the car is. and boy do I hope I'm right, because rereading that i sound really arrogant lol (really, I'm not and I don't mean to be) ;-) -Evan Until next time, Happy Cubing http://www.deepcube.net On 12/24/05, pjgat09 <[EMAIL PROTECTED]> wrote: > > Hmm, lets see. You start with 3 doors, one with a car. The host > cancels out a door giving you 2 doors. That means your guess has a 1/2 > chance of being correct. There is no point in changing, its 50-50 no > matter what. (unless the game is rigged where the car moves from one > door to the next :P ) > > I would stay with my first choice, though it doesnt matter. Its all > personal preferance. > > Peter Greenwood > > --- In [email protected], Pedro <[EMAIL PROTECTED]> > wrote: > > > > Ok, this is off topic, but is interesting... > > > > (please forgive if I make some mistake on the english...) > > Suppose you are at a TV show, where you have 3 doors. 1 of the > doors has a car, and the other 2 don't have anything. So, the show > presenter asks you to choose a door. So, you choose, but he doesn't > open your choosen door. He opens an empty door. Then, he makes a > question: do you want to continue with your first choice or change to > the other door? > > > > What do you do? > > What situation gives you more chances of winning? > > > > Think about it... > > > > Pedro > > > > > > --------------------------------- > > Yahoo! doce lar. Faça do Yahoo! sua homepage. > > > > [Non-text portions of this message have been removed] > > > > > > > > ------------------------------ > YAHOO! GROUPS LINKS > > > - Visit your group > "speedsolvingrubikscube<http://groups.yahoo.com/group/speedsolvingrubikscube>" > on the web. > > - To unsubscribe from this group, send an email to: > [EMAIL PROTECTED]<[EMAIL PROTECTED]> > > - Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service <http://docs.yahoo.com/info/terms/>. > > > ------------------------------ > [Non-text portions of this message have been removed] ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/MXMplB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/speedsolvingrubikscube/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
