The Acme Combination is rated as a two-hour lock, meaning that it takes two hours to crack this lock by an experienced thief. The Smacme company has a half-hour lock that looks exactly the same as the Acme lock and is much cheaper to buy. The XYZ Company wanted to save money, so they bought one Acme lock and one Smacme lock. They put one on their front door and one on the back door of their

building. Explain how an experienced thief should be able to break into the XYZ Company's building in about an hour or less.

What will be an ideal response?

The thief starts working on the front door. If it isn't cracked in a half hour, he
goes to the back door and works on its lock for a half hour. One of the two locks is the
Smacme lock and should open after a half hour of work. If the Smacme lock is on the front
door, the thief breaks into the building in half hour. Otherwise (the Smacme lock is on the
back door), the thief breaks into the building in one hour.