I have a bag containing the digits 0 through 9, and used six of them to stick two different three-digit perfect squares on the foreheads of Paul and George. Both Paul and George know this fact, but each one can see only the other's number.
I ask Paul, "How many of the digits remaining in my bag can you exactly tell me?"
Paul replies, "Three."
If I now ask the same question to George, what should he reply?
(In reply to George's answer
by Bob Smith)
So that actually means he only knows 3: the fourth might be either a 1 or a 7. He doesn't know all 4.
Posted by Charlie
on 2005-08-04 18:05:10