Puzzle

Thorondorito

One of Freddy's beloved
Joined
Jan 4, 2004
Messages
498
ermmmm when you pick up 1 envelope for the first time... are u allowed to see the money in it?
 

Thorwyn

FH is my second home
Joined
Dec 22, 2003
Messages
4,752
solution: http://en.wikipedia.org/wiki/Envelope_paradox

Basically it all boils down to the fact that the probabilities aren´t the same for all values of x. Simply put: it´s more likely to find 100$ in the envelope, than 1.000.000.000.000.000$. And if that´s the case, then we there is no 50% chance.

I think this is a rather nice problem. :)
 

Thorondorito

One of Freddy's beloved
Joined
Jan 4, 2004
Messages
498
Well then, for me its a 50/50 probabilty problem...

If you cant see for the first time the money in it, it doesnt matter whether you swap or not just like it doesnt matter which envelope you started with.

If you can see it you can obtain some useful information to take a decission about swapping or not.

edit: just saw your spoiler after posting :p
 

elisera

Fledgling Freddie
Joined
Sep 3, 2004
Messages
432
Thorwyn[B&Q] said:
solution: http://en.wikipedia.org/wiki/Envelope_paradox

Basically it all boils down to the fact that the probabilities aren´t the same for all values of x. Simply put: it´s more likely to find 100$ in the envelope, than 1.000.000.000.000.000$. And if that´s the case, then we there is no 50% chance.

I think this is a rather nice problem. :)

Thats what I thought, although it does rely on you opening the envelope :)
 

Thorondorito

One of Freddy's beloved
Joined
Jan 4, 2004
Messages
498
So, as i said you need to open it for the first time to have some basis about your decision. If you cant, just simply pick 1.
 

Serbitar

Fledgling Freddie
Joined
Jan 7, 2004
Messages
734
i got frustrated and googled for it, on every site that had this problem they all picked an envelope, opened it and saw what money was inside and then the host offered them the switch.
 

Thorwyn

FH is my second home
Joined
Dec 22, 2003
Messages
4,752
i got frustrated and googled for it, on every site that had this problem they all picked an envelope, opened it and saw what money was inside and then the host offered them the switch.

I only knew it as described. Actually, my version is just a variation of the original problem then, with the added "switch back" feature, that´s accumulating the expected gains. Doesn´t change the idea though. :)
 

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