You must use a gold chain to pay a worker for seven days of service. The chain has seven links on it, and you agree on a price of one link per day.
However, the worker will not work without getting the day's pay up front, and you do not wish to give him more than his due for the fear that he will take it and leave. Therefore, you realised that you must cut some of the links on the chain.
What is the smallest number of links you will need to cut, so that you can make sure that the worker receives one link for every day that he works, but not more?
The solution is based on the notion the worker is willing to return pieces of chain, which is not a certainty. He could have spent the piece that night. Or he might think YOU'LL take off if he returns one. The term "make sure" in the question implies you must be 100% certain. The only way to do that is to make 3 cuts (the 2nd, 4th, and 6th links).