## 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

30 replies to this topic

### #1 ThunderCloud

ThunderCloud

• Members
• 102 posts
• Gender:Male
• Location:New England

Posted 03 February 2013 - 12:44 AM

Three logicians had stickers placed on their foreheads so that none could see their own sticker but each could see one another's. They were told that each sticker has a single positive integer written on it (i.e. 1, 2, 3, ...), and that the sum of the integers on all three stickers is either 8 or 9. They were then asked, in turn, to identify the number on their own sticker. Upon being asked, each logician would name their number if they were sure that they knew it, give up if they were sure that they would never know it, or otherwise 'pass' so that the question would be posed to the next person. The question was repeated, again in turn, until each of the three logicians had either named their number or given up. All three stickers had the same number written on them. Who among the three logicians was able to deduce his number?

• 1

### #2 bushindo

bushindo

Senior Member

• VIP
• 721 posts
• Gender:Male
• Location:Los Angeles, CA

Posted 03 February 2013 - 01:46 AM

Three logicians had stickers placed on their foreheads so that none could see their own sticker but each could see one another's. They were told that each sticker has a single positive integer written on it (i.e. 1, 2, 3, ...), and that the sum of the integers on all three stickers is either 8 or 9. They were then asked, in turn, to identify the number on their own sticker. Upon being asked, each logician would name their number if they were sure that they knew it, give up if they were sure that they would never know it, or otherwise 'pass' so that the question would be posed to the next person. The question was repeated, again in turn, until each of the three logicians had either named their number or given up. All three stickers had the same number written on them. Who among the three logicians was able to deduce his number?

Spoiler for

• 0

### #3 googon97

googon97

Junior Member

• Members
• 21 posts

Posted 03 February 2013 - 02:39 AM

Spoiler for quick logic

Edited by googon97, 03 February 2013 - 02:44 AM.

• 0

### #4 ThunderCloud

ThunderCloud

• Members
• 102 posts
• Gender:Male
• Location:New England

Posted 03 February 2013 - 03:01 AM

Three logicians had stickers placed on their foreheads so that none could see their own sticker but each could see one another's. They were told that each sticker has a single positive integer written on it (i.e. 1, 2, 3, ...), and that the sum of the integers on all three stickers is either 8 or 9. They were then asked, in turn, to identify the number on their own sticker. Upon being asked, each logician would name their number if they were sure that they knew it, give up if they were sure that they would never know it, or otherwise 'pass' so that the question would be posed to the next person. The question was repeated, again in turn, until each of the three logicians had either named their number or given up. All three stickers had the same number written on them. Who among the three logicians was able to deduce his number?

Spoiler for

Spoiler for

• 0

### #5 ThunderCloud

ThunderCloud

• Members
• 102 posts
• Gender:Male
• Location:New England

Posted 03 February 2013 - 03:20 AM

Spoiler for quick logic

Spoiler for

• 0

### #6 bushindo

bushindo

Senior Member

• VIP
• 721 posts
• Gender:Male
• Location:Los Angeles, CA

Posted 03 February 2013 - 03:38 AM

Three logicians had stickers placed on their foreheads so that none could see their own sticker but each could see one another's. They were told that each sticker has a single positive integer written on it (i.e. 1, 2, 3, ...), and that the sum of the integers on all three stickers is either 8 or 9. They were then asked, in turn, to identify the number on their own sticker. Upon being asked, each logician would name their number if they were sure that they knew it, give up if they were sure that they would never know it, or otherwise 'pass' so that the question would be posed to the next person. The question was repeated, again in turn, until each of the three logicians had either named their number or given up. All three stickers had the same number written on them. Who among the three logicians was able to deduce his number?

Spoiler for

Spoiler for

If the two logicians are required to give up if they figure they would never know it, then the game would go as follows

Spoiler for

• 0

### #7 ThunderCloud

ThunderCloud

• Members
• 102 posts
• Gender:Male
• Location:New England

Posted 03 February 2013 - 03:51 AM

Three logicians had stickers placed on their foreheads so that none could see their own sticker but each could see one another's. They were told that each sticker has a single positive integer written on it (i.e. 1, 2, 3, ...), and that the sum of the integers on all three stickers is either 8 or 9. They were then asked, in turn, to identify the number on their own sticker. Upon being asked, each logician would name their number if they were sure that they knew it, give up if they were sure that they would never know it, or otherwise 'pass' so that the question would be posed to the next person. The question was repeated, again in turn, until each of the three logicians had either named their number or given up. All three stickers had the same number written on them. Who among the three logicians was able to deduce his number?

Spoiler for

Spoiler for

If the two logicians are required to give up if they figure they would never know it, then the game would go as follows

Spoiler for
Spoiler for

• 0

### #8 bushindo

bushindo

Senior Member

• VIP
• 721 posts
• Gender:Male
• Location:Los Angeles, CA

Posted 03 February 2013 - 04:18 AM

Three logicians had stickers placed on their foreheads so that none could see their own sticker but each could see one another's. They were told that each sticker has a single positive integer written on it (i.e. 1, 2, 3, ...), and that the sum of the integers on all three stickers is either 8 or 9. They were then asked, in turn, to identify the number on their own sticker. Upon being asked, each logician would name their number if they were sure that they knew it, give up if they were sure that they would never know it, or otherwise 'pass' so that the question would be posed to the next person. The question was repeated, again in turn, until each of the three logicians had either named their number or given up. All three stickers had the same number written on them. Who among the three logicians was able to deduce his number?

Spoiler for

Spoiler for

If the two logicians are required to give up if they figure they would never know it, then the game would go as follows

Spoiler for
Spoiler for

I see what you're saying

Spoiler for

• 0

### #9 ThunderCloud

ThunderCloud

• Members
• 102 posts
• Gender:Male
• Location:New England

Posted 03 February 2013 - 04:34 AM

Three logicians had stickers placed on their foreheads so that none could see their own sticker but each could see one another's. They were told that each sticker has a single positive integer written on it (i.e. 1, 2, 3, ...), and that the sum of the integers on all three stickers is either 8 or 9. They were then asked, in turn, to identify the number on their own sticker. Upon being asked, each logician would name their number if they were sure that they knew it, give up if they were sure that they would never know it, or otherwise 'pass' so that the question would be posed to the next person. The question was repeated, again in turn, until each of the three logicians had either named their number or given up. All three stickers had the same number written on them. Who among the three logicians was able to deduce his number?

Spoiler for

Spoiler for

If the two logicians are required to give up if they figure they would never know it, then the game would go as follows

Spoiler for
Spoiler for

I see what you're saying

Spoiler for
Spoiler for

• 0

### #10 bushindo

bushindo

Senior Member

• VIP
• 721 posts
• Gender:Male
• Location:Los Angeles, CA

Posted 03 February 2013 - 07:19 AM

Spoiler for