Question 185
A company run by several directors has a safe locked with six locks. Each director has three keys, with which they can unlock three different locks. With each key they can unlock exactly one lock.
No two directors can unlock the same three locks, and no two directors together can open the safe. What is the largest possible number of directors running this company?
No two directors can unlock the same three locks, and no two directors together can open the safe. What is the largest possible number of directors running this company?