Brain Teaser
Dh brought this one home today . There are:
5 hats, 2 red and 3 blue
3 girls
The 3 girls stand in a straight line, one behind the other, all facing front.
They each have on a hat, but are unaware of the color of their own hat. The 3rd girl in line is able to see the hat colors of the two girls in front of her. The 2nd girl can see the the hat color of the girl in front of her. The girl in front sees nobody's hat.
The 3rd girl (in the back) says to the other two, "I can see your hats, but I don't know the color of my own."
The 2nd girl says, "I can see the hat in front of me, but I don't know the color of my own."
The 1st girl (in front) says, "I can't see anyone's hat, but I know the color of my own."
What color is the first girl's hat?
posted by Ellen @ 9:12 PM
9 Comments:
At 4:37 AM,
Honey said…
Purple. (Just kidding)
I know both the first two girls can't be wearing red hats, or the third would know her hat was blue. So, that means both the first two girls have to both be wearing blue, or one has red and one has blue.
The second girl knows both she and the girl in front aren't wearing the same color, red, because then the third girl would know what she was wearing. So, the first girl can't be wearing red, because then the second girl would know she was wearing blue since they both can't be wearing red.
Therefore, the first girl is wearing a blue hat.
Thanks for the morning brain teaser!!
At 6:21 AM,
Unknown said…
Mean brain teasers.
And to think Honey hammered that out in a breeze.
I'm still at the there are 5 hats. ;)
Feathers, is the answer. :D
Excellent brain teaser. Now I'll go stand in the corner as I can't figure it out without listening to my brain turn to mush and self-destruct. :D
At 7:46 AM,
Honey said…
Ooh, it hurt my brain, K, I promise. But in a good way. Not like the way chocolate hurts my brain when I've injested enough that the doctors get hershey syrup when they try to draw my blood.
At 8:05 AM,
The Girl You Used to Know said…
you should never make anyone think when they are blog reading.
I may have just popped a blood vessel.
Sigh.
At 8:58 AM,
Honey said…
I guess we're assuming the girls wearing the hats are really smart and logical, right? Because otherwise, if number two got confused, then number one could be wearing red and number two wasn't smart enough to figure out that she must be wearing blue.
At 9:06 AM,
Ellen said…
LOL, H! Yes, the girls are logical--I had a feeling you'd get this one. ;)
K, feathers was pretty much my answer too. Dh just sighed.
Mel--I think you might be right. I'll try to make blog entries free of thought-provocation from now on--wouldn't want to lose the readers. LOL. :)
At 3:06 PM,
Lucy said…
I was thinking about this before I went into work this morning. I thought she had to have on blue but I couldn't figure out WHY she had on blue (pre-caffeine and all). I knew the front two weren't wearing red but the first one could have red and the second one blue.
Okay, I'm confusing myself again...it was blue, let's leave it at that.
At 9:11 AM,
Monica Burns said…
What I want to know is how does the 1st girl know what color her hat is if none of them know as stated in the first paragraph. *grin*
I think the 1st girl has been holding out on people. *grin*
Personally, I'd go with the blue, since there are three.
Monica
At 9:24 AM,
Ellen said…
Blue is definitely the correct answer--see Honey's logic. :)
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