A group of five people want to put a set of locks on a chest and distribute keys to the locks amongst themselves in such a way that all the locks on the chest could be opened only when at least three of them were present to open it.

How many locks would be needed, and how many keys?

(In reply to ?!? Master Key by Stelian Trandafir)

There is nothing tricky or unrealistic about having one key open multiple locks. When the official solution is posted, it will almost certainly specify 10 locks and 5 "master keys". 

Posted by Penny on 2004-03-04 09:58:57