Eight Greatest Ideas for Problem-Solving Strategies
Idea 58: How solutions differ from decisions
Two girls and a woman want to sail to an island. Their boat holds either the two girls or the woman. If all are competent sailors, how can they get to the island in as few trips as possible?
Visualize that end state. If you work backwards from that first trip, you begin to see that someone has to bring the boat back from the island. Thus the two girls must sail over. One girl will remain on the island while the other sails the boat back. And the rest of the problem simply requires keeping track of where everyone is at a given time.
You will notice that in problems like these, all the elements of the solution are already there. All ...