Sorting Gnomes


Room A is full of gnomes who all have their standard pointy hats on, but an evil sorcerer has glued all their hats to their heads and changed some of their hats from the usual red to blue... (i.e. room with N gnomes of which N - X have red hats on and X have blue.) No gnome knows the colour of his own hat

Room B is connected to room A with a door and is currently empty. Neither rooms have anything notable (like mirrors) to aid the gnomes finding out their hat colour.

The sorcerer has set a challenge - the gnomes must go one by one through the door to the other room and once all gnomes have gone through to room B they must be standing in two groups sorted by hat colour (i.e. all the reds in one group and all the blues in the other).

Unfortunately the sorcerer has also set some restrictions... The gnomes are not allowed to communicate with another in any way(no words, winks, head-shaking or anything else!).

You are allowed to help them, BUT you are allowed only one sentance to help them. You can tell this one sentance to each individual gnome or to the group as a whole. The sentance will be the same regardless of both the total number of gnomes and the proportion of gnomes with each hat colour (Assume you are telling them over an intercom!)

The sentance is short, the solution logical and it causes the gnomes to sort themselves into one group of red and one group of blue hat wearers!

(and if you fail the sorcerer will turn YOU into a blue-hatted gnome as well! ;-) )

Think you got the answer? Send it to me and earn eternal (ephemeral?) fame --> Send me an email!
<-- Back