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 Really Simple by DJ)

Compare this to your original "Poor solution" post. It wasn't "really simple" then.

This seems to be a case of 20-20 hindsight, after you read all the other 32 posts. (Post #9 stated "Any two of these people must lack a key to at least one lock. But then the other three must all have a key to that lock; otherwise there would be three people who couldn't unlock it.")

No offense. I do the same thing all the time.

 

 

 

  

Edited on March 4, 2004, 12:49 pm

Edited on March 4, 2004, 1:47 pm

Posted by Penny on 2004-03-04 12:47:17