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 About the keys and locks by Brian Smith)

Sheesh....... Now you clarify this !

The idea that one key opens exactly one lock detracts from the attractiveness of the puzzle. (In my humble opinion, of course). 

There must still be 10 locks.

More shortly........

  

Posted by Penny on 2004-03-04 10:28:43