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# Yellow,Green,Red,Blue

57 replies to this topic

### #31 wolfgang

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Posted 19 January 2013 - 07:15 PM

Another point to clarify.

Must the rows be parallel, and in particular Y-G-R-B order?

OP seems to suggest this condition.

+-------------------------+

|                         |

|      Y Y Y Y Y . . .    |

|      G G G . . . . .    |

Door   R R R R R R . .    |

|      B B B B B . . .    |

|                         |

|                         |

+-------------------------+

Or could the rows e.g. all start at the middle of the room, and grow outward toward the four walls, in any sequence?

Say Yellow to the north, Green to the south, Red to the east and Blue to the west?

Yes...the raws should be as you mentioned in your diagram,but all should face one direction

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### #32 Prime

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Posted 19 January 2013 - 08:36 PM

If the crooks who have already formed 4 neat rows start turning around in their places upon the entry of the next criminal -- that should be deemed as a form of communication by the warden. If they stay put until the newcomer takes his place, he has 3/4 chance of spoiling that neat formation.

If you arrange randomly, say, 16 men in 4x4 formation, no consecutive change of which way they face can guaranty thus newly formed rows' order and same colors in each row.

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Past prime, actually.

### #33 bonanova

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Posted 20 January 2013 - 12:30 AM

Another point to clarify.

Must the rows be parallel, and in particular Y-G-R-B order?
OP seems to suggest this condition.

+-------------------------+
|                         |
|      Y Y Y Y Y . . .    |
|      G G G . . . . .    |
Door   R R R R R R . .    |
|      B B B B B . . .    |
|                         |
|                         |
+-------------------------+

Or could the rows e.g. all start at the middle of the room, and grow outward toward the four walls, in any sequence?
Say Yellow to the north, Green to the south, Red to the east and Blue to the west?

Yes...the raws should be as you mentioned in your diagram,but all should face one direction

"All" in one line? Or "All" in the whole room?

Say the the persons in the red line face the door.
Can the persons in the green line face away from the door?

This is like nailing jello to a tree.
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Vidi vici veni.

### #34 bonanova

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Posted 20 January 2013 - 02:25 AM

I can add something which may help you... The raws may face the door or the opposit direction!

Continuing with the community solve approach, can we clarify:

1. Must all the persons in a particular row face the same direction?
2.
3. If prisoners in say the Yellow row can face in differing directions does that constitute [illegal] communication?
4.
5. Can the first two prisoners choose the time that they [legally] alter their position, at any time up to the last prisoner takes his place?
6.

During making raws...some of them  can be..back to back (in any raw)...but by reaching the last prisoner,they all shoud be at the same direction

But only the first two prisoners can move.

This means the seventh prisoner, say can come into a row back to back with someone else in that row, then at a later time switch his direction so that at the end all in that row have the same direction. So as long as a prisoner stays in the same position, he can flip his direction back and forth during the formation of rows.

That sounds like communication.

Another piece of jello fell off the nail...

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Vidi vici veni.

### #35 wolfgang

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Posted 20 January 2013 - 10:19 AM

I can add something which may help you... The raws may face the door or the opposit direction!

Continuing with the community solve approach, can we clarify:

1. Must all the persons in a particular row face the same direction?
2.
3. If prisoners in say the Yellow row can face in differing directions does that constitute [illegal] communication?
4.
5. Can the first two prisoners choose the time that they [legally] alter their position, at any time up to the last prisoner takes his place?
6.

During making raws...some of them  can be..back to back (in any raw)...but by reaching the last prisoner,they all shoud be at the same direction

But only the first two prisoners can move.

This means the seventh prisoner, say can come into a row back to back with someone else in that row, then at a later time switch his direction so that at the end all in that row have the same direction. So as long as a prisoner stays in the same position, he can flip his direction back and forth during the formation of rows.

That sounds like communication.

Another piece of jello fell off the nail...

Yes....in my OP I said....each prisoner should choose his raw and once he did,he is not allowed to change his mind,but turning around himself was not mentioned

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### #36 bushindo

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Posted 21 January 2013 - 07:07 AM

I can add something which may help you... The raws may face the door or the opposit direction!

Continuing with the community solve approach, can we clarify:

1. Must all the persons in a particular row face the same direction?
2.
3. If prisoners in say the Yellow row can face in differing directions does that constitute [illegal] communication?
4.
5. Can the first two prisoners choose the time that they [legally] alter their position, at any time up to the last prisoner takes his place?
6.

During making raws...some of them  can be..back to back (in any raw)...but by reaching the last prisoner,they all shoud be at the same direction

But only the first two prisoners can move.

This means the seventh prisoner, say can come into a row back to back with someone else in that row, then at a later time switch his direction so that at the end all in that row have the same direction. So as long as a prisoner stays in the same position, he can flip his direction back and forth during the formation of rows.

That sounds like communication.

Another piece of jello fell off the nail...

Yes....in my OP I said....each prisoner should choose his raw and once he did,he is not allowed to change his mind,but turning around himself was not mentioned

This seems to imply that turning around (spinning or rotating) is allowed, even though switching rows isn't allowed. Isn't that a contradiction of the requirement of the OP, which I list below

An unknown number of prisoners( more than 14)were told a day before their execution, that they are going to be blind folded, and a colored paper(either.. yellow,green,red or blue) will be  glued on forehead of each one of them( no one can see his own paper), then they should inter a big hall one by one to make 4 raws in this order( Yellow,Green,Red,Blue)i.e. a raw of Yallows, a raw of Greens  etc.,each one will be unfolded when he inters the hall.No one of them is allowed to arrenge the others,each one should himslf choose where to stay, once he did,he can not change his place( only the first 2 prisoners can change their minds only once). Any kind of comunication between them is not allowed. If any one of them stands in a wrong raw, all of them will die!
All colores were used.
They should make a plane which saves all of them, can you help them?

Communication is defined as 'the imparting or exchanging of information or news', so by any reasonable interpretation, turning-in-place is considered a violation of the rules. If communication is allowed, then the puzzle becomes trivial. In fact, we don't even need to allow the first 2 prisoners to change their minds if we allow them to communicate.

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### #37 bonanova

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Posted 21 January 2013 - 11:55 AM

Agree that now it's not difficult.

But the first two might need change row locations.

Suppose the first three prisoners were [1] all red, [2] all different colors.

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Vidi vici veni.

### #38 CaptainEd

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Posted 21 January 2013 - 05:12 PM

OK, I think we are agreeing that we have to relax our interpretation of Wolfgang's proscription against communication.

The first two prisoners can establish the locations of all 4 colored rows, before the third one enters the room.

Then, the prisoners can inspect each arriving prisoner, rotate their positions to indicate the newcomer's color, and the newcomer can take his place in the appropriate row.

Spoiler for Details of establishing the locations

Spoiler for Conveying position to next arrival

Edited by CaptainEd, 21 January 2013 - 05:14 PM.

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### #39 CaptainEd

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Posted 21 January 2013 - 05:30 PM

Spoiler for I always have typos...

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### #40 wolfgang

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Posted 21 January 2013 - 06:29 PM

Spoiler for I always have typos...

OK, I think we are agreeing that we have to relax our interpretation of Wolfgang's proscription against communication.

The first two prisoners can establish the locations of all 4 colored rows, before the third one enters the room.

Then, the prisoners can inspect each arriving prisoner, rotate their positions to indicate the newcomer's color, and the newcomer can take his place in the appropriate row.

Spoiler for Details of establishing the locations

Spoiler for Conveying position to next arrival

your method is successful with the first two prisoners, but you should find a very simple,uncomplicated way for the 3rd one,if you find it, the rest will be  very easy and straight forward job.

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