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Hidden Number Guess (Posted on 2013-07-10) Difficulty: 4 of 5
Alex and Bob are given a list of N distinct integers and are told this:

Six distinct integers from the list are selected at random and placed one at each side of a cube. The cube is placed in the middle of a rectangular room in front of its only door, with one face touching the floor, 4 of its 6 sides parallel to the walls of the room.

Bob must enter the room and is allowed to alter the orientation of the cube, with the restriction that afterwards its in the same place with one face touching the floor and its 4 sides kept parallel to the 4 walls of the room. Bob will then be sent away, after which Alex can enter the room and is allowed to observe the 5 visible sides of the cube.

What is the largest N that guarantees that Alex will to be able to determine the number on the bottom of the cube and what should Alex instruct Bob to do with the cube for that N?

No Solution Yet Submitted by K Sengupta    
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Comments: ( Back to comment list | You must be logged in to post comments.)
re(2): an answer | Comment 3 of 4 |
(In reply to re: an answer by Ady TZIDON)

There seems to be a flaw in my previous proposed solution. Though using it as a basis, the number of arrangements of the cube to indicate the bottom unseen number may be 16. 
The cube can be arranged to indicate up to 6 sequential values less than, between, or greater than a given the five visible numbers. Yet, these sequential strings of values need overlap to allow for certainty of designation, thus the number of possibilities is 6+5 + 5, for the visible numbers = 16.  Both Bob and Alex would need to understand and follow the same scheme to implement this, which I will will agree with Ady that it would be difficult. Yet, I believe is possible.

Is there a solution that can account for a larger value of N?

Edited on July 16, 2013, 11:59 pm
  Posted by Dej Mar on 2013-07-13 05:42:25

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