Riddle

If the red house has blue shutters and the green house has red shutters, what's this section for?
Sheepay
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Riddle

Postby Sheepay » Sun Jan 20, 2013 4:22 pm

https://dl.dropbox.com/u/75977546/riddle.png
You can see 4 people in the picture. The green arrow indicates the direction that they are looking at. Which person will speak up and say the color of their hat?

- They know that there are 4 people in total who are wearing a hat.
- They know that there are 2 red hats and 2 blue hats.
- The 3rd person can see both the hat color of number 1 and the hat color of number 2. (Counting from left to right of course.)
- They do not know the color of their own hat and may not look at it either.
- They may not communicate in any way or form unless it is to say the color of their hat.
- This riddle does not have an obscure solution like: "They can look around the globe." It's simple once you know it.

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Pyrrho
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Re: Riddle

Postby Pyrrho » Sun Jan 20, 2013 5:19 pm

Person 2 is the first to tell the color of his own hat.

Each person knows that their hat is either red or blue.

Only Person 2 and Person 3 can see the color of another person's hat.

Person 2 knows that Person 1's hat is red.

Person 3 knows that Person 1's hat is red and Person 2's hat is blue.

Person 2 is the only person who can tell the color of his own hat.

My solution:


Spoiler:
Person 2 knows that if his hat was RED, Person 3 would see that both Person 1's hat and Person 2's hat were RED, therefore, Person 3's hat would have to be BLUE. Person 3 cannot know the color of his own hat.

Since Person 1's hat is RED, Person 2's hat must be BLUE.

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Sheepay
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Joined: Sat Jan 19, 2013 10:20 pm

Re: Riddle

Postby Sheepay » Sun Jan 20, 2013 5:20 pm

Correct! Well done.

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Austin Harper
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Re: Riddle

Postby Austin Harper » Wed Jan 23, 2013 3:30 pm

Good job, Pyrrho.
I got the same result but not for as good of a reason.
Spoiler:
Person 1 and Person 4 have no idea what color anyone's hats are so they won't guess.
Person 3 knows Person 1's hat is red and Person 2's hat is blue so there's still a 50% chance his hat is either color.
Person 2 knows that Person 1's hat is red and doesn't know the rest so there's a 33% chance his hat is red but a 67% chance his hat is blue, so he would pick blue because it's more likely but not certain. I didn't think about Person 2 thinking about what Person 3 would say.
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