## Welcome to BrainDen.com - Brain Teasers Forum

 Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account. As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends. Of course, you can also enjoy our collection of amazing optical illusions and cool math games. If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top. If you have a website, we would appreciate a little link to BrainDen. Thanks and enjoy the Den :-)
Guest Message by DevFuse

# Christmas Tree

44 replies to this topic

### #41 thegirlyouneverknew

thegirlyouneverknew

• Members
• 112 posts

Posted 23 April 2008 - 02:48 AM

I'm pretty sure that whatever way this goes, the answer has to be "A"
• 0

### #42 stpuggy

stpuggy

Newbie

• Members
• 1 posts

Posted 25 May 2008 - 06:07 PM

D. would win. This being said because it could always look at the twig ;3
• 0

### #43 entaras

entaras

Newbie

• Members
• 1 posts

Posted 05 November 2008 - 09:43 PM

It depends on which angels have which color. If B and C are either both blue or both yellow, then A will instantly say "I am (insert other color here)." If B and C are different colors, then A will not say anything. In this instance, B will say to herself "A doesn't know what she is, so C and I are different colors, and since C is x, I am y." D just uses up the second of whatever color isn't used twice in the above angels.
• 0

### #44 nutcracker

nutcracker

Newbie

• Members
• 1 posts

Posted 09 July 2009 - 11:07 AM

B will be the winner and his color would be Blue (or Yellow) if C's halo is Yellow (or Blue). The logic goes like this:
1. A (top MOst): Can see everyone's halos except Ds: He can answer only if B and C have same colors. Fore.g. if B and C have Yellow then he will know he and D have Blue color halos. But in case B and C have different color halos, A can't be sure whether he has Blue or Yellow.

2. B knows taht A has now shouted the answer, so B's and C's halos are not of same colors. They have to be different for A to not to should out the answer. So B has to just look down for C's color. If C is Blue,then B is Yellow, else vice versa.

So B is the winner.
• 0

### #45 uokspydr

uokspydr

Newbie

• Members
• 1 posts

Posted 08 October 2009 - 05:52 AM

The wording should be changed to say that the Angels actually speak their guess out loud. I read "guess" as "silently figuring it out" because "guess" is an internal thought process, at which point I concluded that A was the only one with any hope of figuring out his own color and only when B&C have the same colors as each other.

So, when a guess IS possible, it's only A that can do it... unless the wording is changed.

Not completely true. If A saw that B and C had the same color, A would immediately know that it's color was the other one. If A saw that B and C had different colors, A would not be able to make a guess. When A didn't speak, B would realize that A did not know, and therefore B would know that B and C must have different colors. Knowing that it's color was not the same as C, B would be able to determine that it's color had to be the other one.

So if B and C's colors were the same, A would be able to guess. If A could not guess, B would know it's color was the other color from whatever color C is.
• 0

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users