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?

Hi all

I have a possible solution to the problem:

if you have a combination of 5 people of which any 3 have to be able to open all the locks then you have to have a C(5,3)=10 unique locks and 3 cheys per lock = 30 keys divided by 5 people = > 6 keys/ person

 

Posted by Stelian Trandafir on 2004-03-04 07:28:29