A problem for you to solve :)

[Kardan]

Considering we all use the internet so much, you may have seen this before... And seeing it on the BBC reminded me of it today, so I thought I'd bring it up to see what people think :) If you have seen it before, please try and not spoil the answer straight the way :P

So, you're on a gameshow. You are stood infront of 3 doors, and have to pick a door. Whatever is behind the door, you will win as your prize. Behind one of the doors is a sports car, behind the other two doors is a rubber duck.

You are asked to pick a door, A, B or C. After you have made your choice, the host of the gameshow opens a door you didn't pick, and reveals a rubber duck. There are two doors left unopened, the door you picked, and the other door you didn't pick. The host says you can stick with your pick, or change your pick to the other door.

What do you do? What is the best way to try and win the car? What are the odds of winning the car after one rubber duck has been revealed?

As I said before, if you've heard the puzzle before, you can just say 'Yeah, I know this one :P' or something :)

[sex]

isn't it just 50/50 so i'd just stick

[Cerys]

Yep done this in maths

even had a question on it in our freakin' maths gcse exam.. xD

[Kardan]

isn't it just 50/50 so i'd just stick

No :P

[FlyingJesus]

Saw Derren Brown do a similar thing but just like ball in a cup type trick and he tried to explain (to the guy who had to pick) that there is a greater chance of it being one than the other because the host had to pick a door that was a duck and some nonsense about the 1/3 chance went to a 1/2 and then multiply it by giraffe and split the differential wormhole to get a new set of odds but the very simple fact remains that there are two doors and one big prize behind one of them guaranteed. Whatever gymnastics you put it through there are 2 doors and 1 of them has a car behind it, so there is a 1/2 chance of winning whichever you pick. You don't need to do lottery mathematics on switching 1/3 to 1/2

[Kardan]

Saw Derren Brown do a similar thing but just like ball in a cup type trick and he tried to explain (to the guy who had to pick) that there is a greater chance of it being one than the other because the host had to pick a door that was a duck and some nonsense about the 1/3 chance went to a 1/2 and then multiply it by giraffe and split the differential wormhole to get a new set of odds but the very simple fact remains that there are two doors and one big prize behind one of them guaranteed. Whatever gymnastics you put it through there are 2 doors and 1 of them has a car behind it, so there is a 1/2 chance of winning whichever you pick. You don't need to do lottery mathematics on switching 1/3 to 1/2

...But it isn't a 1/2 :P And if Derren Brown did it, then it's none of his mumbo jumbo, it's just simple maths :P

[lemons]

SWAP DOOR FOR 66 PERCENT CHANCE

i did this in maths last year i think

[myles]

obviously ud see the car poking out behind the door????????????????????????????????????

[Matthew]

You would switch as there's only a 1/3 chance that you pick the car door first time. There's a 2/3 chance that the car is in one of the other 2 doors, so when the host gets rid of one of them then there's a 2/3 chance that the remaining door has the car. I think that's right, my teacher mentioned it earlier this year!

[e5]

Heard this before... but i'm not 100% sure I remember the answer...

[Shockwave.2CC]

well if you picked a door and they opened another door and in that door was a rubber duck and they said you can swap the door that is open for one of the other doors. Then I would just gamble as this time you know your going to get a rubber duck (which you would of got if you stuck with the door that's already been opened) or a sports car. So it's like 50/50.
Yuxin; will rather have a rubber duck than a sports car anyways.

[FlyingJesus]

Oh I read up on it, didn't realise the host would know which door to pick :P yeah makes sense if they do it on purpose

[Matthew]

well if you picked a door and they opened another door and in that door was a rubber duck and they said you can swap the door that is open for one of the other doors. Then I would just gamble as this time you know your going to get a rubber duck (which you would of got if you stuck with the door that's already been opened) or a sports car. So it's like 50/50.
@Yuxin (http://www.habboxforum.com/member.php?u=63975); will rather have a rubber duck than a sports car anyways.

its not 50/50 :P

[karter]

obviously ud see the car poking out behind the door????????????????????????????????????

LMFAOOOO OMG

anyway someone explain this

[Matthew]

LMFAOOOO OMG

anyway someone explain this

read my post in the spoiler

[wixard]

my brain

it hurts

[Aiden]

I would stick... I don't drive anyway :) I've also seen this on Derren Brown.

[Stephen]

I wonder what Yuxin; would do........

[Gina]

well i cant drive so a car doesnt interest me very much
so i'd open any door and be happy with whatever it is
why would i need to take the time and effort to solve the problem
i would be happy with a rubber duck

[Stephen]

I get it now

Odds are always gonna be against you when you pick your door because it's a 1/3 chance
and if the first door opened isn't the car then your odds just got lower because there was more of a chance of it being in a door you didn't pick
so now you've got rid of 1 out of 2 of the doors you didn't pick so switching to that other door puts the odds on your side