Sailor Cat needs to bring a wolf, a goat, and a cabbage across the river. The boat is tiny and can only carry one passenger at a time.

If he leaves the wolf and the goat alone together, the wolf will eat the goat.
If he leaves the goat and the cabbage alone together, the goat will eat the cabbage.

How can he bring all three safely across the river?

http://www.mathcats.com/explore/river/crossing.html