Every other Wednesday I go to a kind of game playing association.The games are very varied and this evening I found myself playing a card game with two young girls. The rules of the game weren't quite clear and we weren't sure if we were meant to choose two cards from eight (therefore discarding two) blind or if we were meant to be able to see the cards. These cards were just character cards used to begin each round of play. The order of play in each round came into the equation but I was basically arguing that we should be able to see the cards, otherwise choosing first held no advantage. The two girls argued that if you chose first, even blindly, then you held a higher probablity of getting the card you wanted. I argued that choosing first changed nothing since they'd be just as likely to leave me the cards I want anyway.
Basically then we disagreed over the law of probability. I was sure I was right but as it was 2 against 1 we carried on choosing the cards blind.
So Lifers: who was right - me or the two girls?
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Two girls were shagged on a table and they were blind, what are the odds on that?
Or something like that.
If they went first the first bird has those odds of getting them two cards as well .... But by getting just one of them they stop you from getting the two so 1 in 4 (so 3 in 4 chance in your favour)then a 2 in 7 (5 in 7 for you) ... So if both are missed then for the next person it's 1 in 3 (2 in 3 for you) and then 2 in 5 (3 in 5 for you)... Then if still missed you have a 1 in 2 and 1 in 3 chance of getting them ....
Someone with a more mathematical mind will explain the numbers but I'm reckoning/guessing you've got more chance going first
Having re read that I can't work it out but using what I think is the right method you may be right
1 x 1 and 4 x 7 is 1 in 28 chance
Then 3 x 5 x 2 x 3 x 1 x 1 (90) and 4 x 7 x 3 x 5 x 2 x 3 (2520) which is 1 in 28 as well
So I've changed my mind so you're right
Almost like working out our home/away ratio :-) boreoff.com
There's gotta be someone out there who can confirm one way or t'other
If you pick the card blindly you have a set chance 1/8 of picking that card.
If someone else picks the other cards (again blind) you still have the 1/8 chance, it's just that you have less choice over which ones you get to pick. The only time the odds change is when the actual cards picked are revealed.
Let's assume the following:-
- There are 8 cards on the table, ranked (in order of preference) 1-8, where 1 is the best card, and 8 is the worst.
- The order of preference is the same for both players. This is important.
- The players are 'intelligent' (i.e. given the choice, will always choose the best available card).
Let's now look at the odds of getting the 'top' card.
If the cards are face-up, player 1 will always pick the 'top' card (100%). The chance of player 2 taking the top card are therefore 0%.
If the cards are face-down, the chance of player 1 taking the top card are 1/8, or 12.5%.
In order for player 2 to get the top card, it must first be avoided by player 1 (7/8 chance), and then randomly chosen by player 2 (1/7 chance). The chance of this happening are therefore 7/8 * 1/7 = 1/8 (12.5%).
There is therefore no advantage to going first if playing 'blind'.