A businessman has two cubes on his desk. Each cube has a number on each of its sides. Every day, the businessman arranges the cubes in such a way that the upward facing numbers display the day's date. (Note that both cubes are always used for this, so on the 7th of the month, the cubes' surfaces display "07".)

How are these cubes numbered? (I.E. What numbers are on which cube? - call them C₁ and C₂.)

(From http://www.ocf.berkeley.edu/~wwu/riddles/intro.shtml)

(In reply to re: My Solution by humfoozneydannle)

As the requirement is to display both cubes for the day of the month, you do need the 0 on both cubes. Thus, you do need to use the inverted 6 as a 9 for the 09^th, 19^th and 29^th (or vice versa for the 06^th, 16^th and 26^th) of the month.

One of the possible solutions:
C₁ : 0, 1, 2, 3, 4, 5
C₂ : 0, 1, 2, 6, 7, 8


If permitted to display one cube for the first 9 days of the month, one would then not need to use an inverted 6 as a 9 (or vice versa), and may, have the following as a solution:
 
C₁ : 0, 1, 2, 3, 4, 5
C₂ : 1, 2, 6, 7, 8, 9

Posted by Dej Mar on 2008-09-16 02:46:06