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# Whatchya Gonna Do (2 goats and a car)

196 replies to this topic

### #191 aaronbcj

aaronbcj

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Posted 22 October 2010 - 11:24 AM

Again, i got this 1 nagging.
Hpw many times would host open a door, had i selected wrongly at first go.

If opening a door is simply optional for host, i will STICK.
if opening a door is part of the game(always), i will SWITCH.
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Posted 09 November 2010 - 02:42 PM

you change your choice due to variable change, when you first picked you had a one in three chance of getting the car, now you have a one in two chance, but you must change your opinion for the odds to go up
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### #193 Maquis

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Posted 09 November 2010 - 09:52 PM

you change your choice due to variable change, when you first picked you had a one in three chance of getting the car, now you have a one in two chance, but you must change your opinion for the odds to go up

No, I disagree with your odds. The puzzle is assuming that the host knows where the car is and also assumes that the host will open one of the losing doors everytime no matter what you chose.

When you first select a door, you have a 1/3 chance of picking the car. (Or, a 2/3 chance of picking wrong). If you switch, you now have a 2/3 chance of winning the car. The host helps you win by always eliminating a wrong choice.
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### #194 gerfome

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Posted 06 January 2012 - 12:28 AM

She should stick to her original choice. the game host would only want her to change doors, if he knew she had won the Jag, so he tempts her to change.
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### #195 bhramarraj

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Posted 13 September 2012 - 08:13 AM

Say you are given a heap of 50 coins, in which only one coin is real, while all other coins are fake. you can not recognize the fake or real coin by seeing or touching them.
When you grab a coin from the heap of 50 coins, there was only one out of 50 chances that you grabed right coin.
Suppose the host now removes 47 fake coins. Only two coins are left in the heap and one in your hand. Now what you will do?
Stick to the coin which you selected When there were 50 coins and there was only a very remote chance that the coin selected was real...?
OR
You will leave that and grabe another coin....?

Definitely when you do not know which coin is real, you shall like to leave the coin in hand which had more chances to have been fake, and grab a new coin which has now better chances to be real.
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### #196 MuckersMate

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Posted 16 September 2012 - 05:33 PM

Swap.
33.3 % before for the girl, 66.6% for the host.

The odds haven't changed, but the host is offering her his 66.6%probability.

Take it.
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### #197 MuckersMate

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Posted 16 September 2012 - 06:54 PM

No, I disagree with your odds. The puzzle is assuming that the host knows where the car is and also assumes that the host will open one of the losing doors everytime no matter what you chose.

When you first select a door, you have a 1/3 chance of picking the car. (Or, a 2/3 chance of picking wrong). If you switch, you now have a 2/3 chance of winning the car. The host helps you win by always eliminating a wrong choice.

No, I disagree with your odds. The puzzle is assuming that the host knows where the car is and also assumes that the host will open one of the losing doors everytime no matter what you chose.

When you first select a door, you have a 1/3 chance of picking the car. (Or, a 2/3 chance of picking wrong). If you switch, you now have a 2/3 chance of winning the car. The host helps you win by always eliminating a wrong choice.

No, I disagree with your odds. The puzzle is assuming that the host knows where the car is and also assumes that the host will open one of the losing doors everytime no matter what you chose.

When you first select a door, you have a 1/3 chance of picking the car. (Or, a 2/3 chance of picking wrong). If you switch, you now have a 2/3 chance of winning the car. The host helps you win by always eliminating a wrong choice.

Correct.

Variable change.
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