Price is Right -- Probablity Puzzle

[metsandfinsfan]

http://forumserver.twoplustwo.com/showfl...rue#Post6117188

[HP]

[ QUOTE ]
I got a better puzzle:
me and two of my friends, ill call the pma and stem, check into a love shack hotel, purely by mistake. we didn’t know it was a lovers retreat, we really didn’t.
manager guy charges us $30
later when we are in our room (not having sex mind you) he remembers its only $25.
manager guy says [censored] those ghey guys and pockets the $5.
question is, how did we all fit into the hot tub?

[/ QUOTE ]

ROFL

i may steal this in the future

[metsandfinsfan]

[ QUOTE ]
I got a better puzzle:
me and two of my friends, ill call them pma and stem, check into a love shack hotel, purely by mistake. we didn’t know it was a lovers retreat, we really didn’t.
manager guy charges us $30
later when we are in our room (not having sex mind you) he remembers its only $25.
manager guy says [censored] those ghey guys and pockets the $5.
question is, how did we all fit into the hot tub?

[/ QUOTE ]

no soap, radio

[DavidC]

I already know the answer, though I still don't know the reasoning behind it from a math perspective, but it finally clicked.

Basically, when one of the first two doors (that you didn't pick) shows a donkey, the second of those doors becomes more likely not to contain a donkey than a random door.

But I don't know how it works, from a math perspective.

If bob were to pick a random door from the two, rather than purposely picking a donkey, and he happened to show you a donkey, then you would be indifferent between the door you chose and the other remaining door, correct?

[LuckayLuck]

[ QUOTE ]
If bob were to pick a random door from the two, rather than purposely picking a donkey, and he happened to show you a donkey, then you would be indifferent between the door you chose and the other remaining door, correct?

[/ QUOTE ] yes

I don't quite know how the math works too, but it can be pretty extreme. For example...


suppose there are ONE HUNDRED doors.

You pick one. Bob opens 98 doors with donkeys in them. You should switch.

If you switch, you'll have a 99/100 chance of getting a million dollars. Otherwise, you have a 1/100 chance.

[coxquinn]

[ QUOTE ]
I already know the answer, though I still don't know the reasoning behind it from a math perspective, but it finally clicked.

Basically, when one of the first two doors (that you didn't pick) shows a donkey, the second of those doors becomes more likely not to contain a donkey than a random door.

But I don't know how it works, from a math perspective.

If bob were to pick a random door from the two, rather than purposely picking a donkey, and he happened to show you a donkey, then you would be indifferent between the door you chose and the other remaining door, correct?

[/ QUOTE ]

The best way I can explain it is you Assume he will ALWAYS show a door with a donkey behind it, no matter what door you pick. Therefore when you first pick a door your probability is 1/3 and him showing you a donkey is expected and does not change your probability. Sort of like position in poker/blackjack--Bob Barker picks a door to open AFTER you select yours, and there is always a door w/ a donkey to show you, so you are still getting 1/3 odds.

That probably made it more confusing, whatv

[Neil S]

I first ran into this in college. I didn't believe it, so I sat down to write a simulation to prove it. I realized the correct answer's correctness when I got to the point where I implemented the fact that Monty Hall is guaranteed to open a donkey door.

[shortline99]

quinnnnnnnnnn

remember that time you got drunk and missed turning stone

[coxquinn]

[ QUOTE ]
quinnnnnnnnnn

remember that time you got drunk and missed turning stone

[/ QUOTE ]

omg yea i totally forgot about that. im awesome

[coxquinn]