All days of the year host an annual celebration.
January 14 is a day of the year.
Therefore January 14 hosts an annual celebration.
Which it does: World Logic Day is a Unesco-approved date in the academic calendar for the promotion of the study of deductive reasoning. It falls next week, but here is a problem to get you in the mood.
Middle management
Andy, Bea, and Celine have a jar of ten cookies. They will take turns putting their hands in the jar to take out cookies for themselves. Andy is first, then Bea, then Celine. On each turn, they can take as many as they like.
They agree to the following conditions:
1) No one wants to end up with the most, or the least number of cookies. (To have the most looks greedy, to have the least looks lame.) Finishing with joint most, or joint least, is as undesirable as finishing with most or least.
2) They want as many cookies as possible. (Always better to have as many cookies as you can.)
If condition 1 has priority over condition 2, but both are desirable, how many cookies does each friend end up with?
The friends are not allowed to communicate or form alliances. They do not need to take all the pieces, and one or more could take nothing. Assume that they are acting rationally and in their best interests.
I’ll be back at 5pm UK with the solution.
UPDATE: Solution can be read here.
PLEASE NO SPOILERS. Instead discuss your favourite illogical arguments.
Thanks to Deniz Sarikaya of World Logic Day for today’s puzzle. A list of WLD events are listed here.
If you would like a harder set of puzzles, try this Christmas Puzzle competition.
I’ve been setting a puzzle here on alternate Mondays since 2015. I’m always on the look-out for great puzzles. If you would like to suggest one, email me.
