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 key answer by Ady TZIDON)

You should "easily show" it's a minimum. Also, there are 10 locks and 6 keys. So which keys are for which locks, and how much of each?

This solution is an outline, but it isn't close to a proof.

Posted by Gamer on 2004-03-03 17:57:39