The Wolf, the Goat and the Cabbage
A farmer must get a wolf, a goat and a cabbage across a river. His boat is small: he can take only one of the three with him on any crossing.
And he cannot leave just anything together on a bank while he is on the water:
- the wolf and the goat alone → the goat is eaten;
- the goat and the cabbage alone → the cabbage is eaten.
With the farmer present, nothing is eaten.
One passenger per crossing — and an empty boat still counts as a crossing.
Answer to type: the smallest number of river crossings that gets all three across. Count every trip the boat makes, in both directions, including the ones where the farmer travels alone.
💡 I want a nudge
Something has to come back across the river. Ask yourself which of the three is the troublemaker.
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Answer: 7
- Take the goat across. (Wolf and cabbage are safe together.)
- Come back empty.
- Take the wolf across.
- Bring the goat back — the move nobody expects, and the one the whole puzzle turns on.
- Take the cabbage across. (Wolf and cabbage, safe again.)
- Come back empty.
- Take the goat across. Seven crossings.
The trick: the goat is in both dangerous pairs, so it can never be left with either of the others — it has to be the first one over and the last one over, which forces you to carry it back once. Finding the object that appears in every constraint, and building the plan around it, is the standard first move.