Brainteaser 1 - a warm-up
A ferryman has a wolf, a sheep and a head of cabbage, and he wants to transport all three from one side of the river to the other.
However, his small ferry has room for only one possession at a time. This means that if he wants to cross the river with one of his possessions, he has to leave the other two behind. If he leaves the sheep alone with the cabbage, it will eat it. If he leaves the sheep alone with the wolf, it will be eaten.
How can the ferryman nonetheless bring all three of his possessions safely to the other side of the river?