After blindfolding them, Paul picks up the five red discs, sticks one on the forehead of each logician, and hides the other discs elsewhere. After removing the blindfolds, everyone sees the discs (all red) on the others' foreheads but not the one on his own.

After a few minutes, one of the logicians (that reasons a little faster than the others) correctly states the color of his disc. How does he work it out?

ok i really liked this problem so i hope this response isn't offensive...

i think "faster" is too relative here

if one is a little faster (a.k.a. slower), then the other 4 could see the green or blue on the fast guys head and still not answer in time.

if one is a little slower (a.k.a faster), then the other four would see the non-red on the slow guys head and wait so that he could shout out red too quickly and be wrong.

hence the only good *solution* would be to change the *problem* such that all 5 are equal and shout RED at the exact same time.

:)

Edited on October 15, 2005, 2:10 am

Posted by tanx on 2005-10-15 02:06:40