Rolex has five pieces of chain each containing four links He wants to join the pieces to form a circle If it costs 10 cents to open a link and 10 cents to close a link find a way he can do this for?

To join the five pieces of chain into a circle, Rolex can open one link from any piece of chain, use it to connect to the next piece, and then close that link. This requires opening one link and closing one link, costing a total of 20 cents. By using this method, he efficiently connects all the pieces into a single circular chain with minimal cost.