Riddle/Brain Teaser

by **Stl Lunatic** » Sat Sep 16, 2006 9:46 pm

Ok so I have a riddle for you guyes. I actually was given this problem over the weekend for my math class, and I figured it out...lets see if you can solve it.

(fyi it is possible to prove what happenes...although it seems impossible)

There is 3 guys who are in prison waiting on death row. They are set to be killed in 10 days. One is blind, one is half blind, and the third can see normal. It is the wardens birthday so he deciedes to play a game with the 3 inmates on deathrow. He sets up a box with 5 hats in it. 3 red and 2 white, he then lets them pick a hat from the box and puts it on their head. They cannot see the color of their own hat but can see the other two men. The warden says if you can guess what color your hat is I will let you free if you guess wrong then I will kill you right now or you can surrender and say you don't know and I will send you back to prison for the rest of your life. He also says there is no talking or cheating of any kind. So the normal visioned man goes first and looks at the two inmates and says "I don't know, I give up" so he goes back to jail for the rest of his life. The second person, the half blind man says "well I don't know either" and he goes back to prison also. The blind man now says "I know what hat I'm wearing" and correctly guesses his color and is set free.

How did the blind man know for sure what color he was wearing?

by **Sabres** » Sat Sep 16, 2006 11:29 pm

I have no idea...

please pm me the answer though so I don't go nuts! haha

by **petersapien** » Sat Sep 16, 2006 11:53 pm

Blind luck??

by **King** » Sun Sep 17, 2006 12:02 am

The guy who is able to see and the half blind guy both have the same color hat on. when both say they do not know, the blind guy knows that both of the red hats are being worn and guesses he is wearing a white hat.

Thats about as close to an answer with some sort of twisted logic that i can get to it.

by **Slaughter2** » Sun Sep 17, 2006 1:19 am

instead of trying to learn math, try some spelling class first......I know what the answer is, this was one of my questions in math class in '90 when I was a senior in high school (ouch), it was wording a little different but yes the same concept

clue:

he then lets them pick a hat from the box and puts it on their head

(taking right from his post)

by **cavalierlwt** » Sun Sep 17, 2006 2:21 am

Thought I had it, I'm wrong,

by **Gen. Ouch** » Sun Sep 17, 2006 3:32 am

very strange riddle.

by **Stl Lunatic** » Sun Sep 17, 2006 9:52 am

Let me put it this way it takes a bit of work to come up with a perfect answer as to how he knew for sure his hat color...I will tell you this he knows his hat is red...If you want the answer before I post it here say so and I will PM you the answer...

The geist of this puzzle isn't as much what hat color he is wearing it is how he knows because anyone could guess one way or the other...60-40 chances...ANother thing to look at is noone is going to guess their hat color unless their apsolutely sure since he will kill them on the spot if they are wrong.

by **[ecgn] btt** » Sun Sep 17, 2006 10:15 am

The blind guy picked the hat. The warden puts it on his head. Passing his nose. He smells the dye that makes it red. That's my guess.

by **cavalierlwt** » Sun Sep 17, 2006 10:24 am

I had it 90% solved, did nearly everything important, ie, laid out all the possibilities in a grid, and started removing impossibilities. I failed to see the inductive reasoning, I only used deductive reasoning...that's where I blew it.

Condition for knowing=seeing two red hats, which means you are wearing the white hat.

edit, I don't want to give it away, but here's big hint

-#1 reaction (what he didn't see)
-what #2 saw PLUS number #1's reaction to what #2 can see.

by **Gen. Ouch** » Sun Sep 17, 2006 1:06 pm

how many people actually solved it?

by **DrNoob** » Sun Sep 17, 2006 5:17 pm

Possible permutations
p1) W R R
p2) W W R
p3) W R W
p4) R W W
p5) R W R
p6) R R W
p7) R R R

Assume that if either inmate #1 or #2 saw both other hats as white, then own hat must be RED.

1st "don't know" rules out p4 (didn't see both white hats)

2nd "don't know" rules out p3 (same reason)

Only permutation left with #3 having white hat is p6. The probability of having RED hat is now 4/5 or ~80%. I can't think of way to getting rid of p6, but if sentenced to death with probability of 100%, but 80% chance of getting off by guessing RED, then definitely a good gamble for the 3rd/Blind inmate to guess RED. Maybe someone else can see how to get rid of p6.

by **SavageParrot** » Sun Sep 17, 2006 6:43 pm

The first guys doesn't see 2 white hats otherwise he'd have know he was red. The second guy doesn't see 2 white either. That Eliminates options 3 and 4. Option 6 is removed by assuming the second guy has a brain. If he does he can't have seen a white hat on the blind guy because if he had he would know his own hat was red because if it was white the first guy would have walked free. Therefore as neither of the first 2 guys walked free the blind guy knows his hat has to be red...

by **Jungle_Fowl** » Sun Sep 17, 2006 10:41 pm

Originally posted by Stl Lunatic
There is 3 guys who are in prison waiting on death row. They are set to be killed in 10 days. One is blind, one is half blind, and the third can see normal. It is the wardens birthday so he deciedes to play a game with the 3 inmates on deathrow. He sets up a box with 5 hats in it. 3 red and 2 white, he then lets them pick a hat from the box and puts it on their head. They cannot see the color of their own hat but can see the other two men. The warden says if you can guess what color your hat is I will let you free if you guess wrong then I will kill you right now or you can surrender and say you don't know and I will send you back to prison for the rest of your life. He also says there is no talking or cheating of any kind. So the normal visioned man goes first and looks at the two inmates and says "I don't know, I give up" so he goes back to jail for the rest of his life. The second person, the half blind man says "well I don't know either" and he goes back to prison also. The blind man now says "I know what hat I'm wearing" and correctly guesses his color and is set free.

What type of prison system are you guys running down there? :eek:

Next your going to tell me your trials are based on what a monkey decides. j/k :lol:

by **=ender=** » Sun Sep 17, 2006 11:30 pm

Easy... blind guy knows what colors smell like. Sheesh. No math necessary.

Riddle/Brain Teaser

Riddle/Brain Teaser

Re: Riddle/Brain Teaser

Who is online