For those who enjoy challenging brain teasers, there is one that has challenged the sharpest of minds for over 1,000 years. Known as the River Crossing Puzzle, it first appeared in the medieval Latin manuscript Propositiones ad Acuendos Juvenes (“Problems to Sharpen the Young”) in the late 9th century.
The puzzle, as it is commonly expressed, is as follows:
Once upon a time a farmer went to a market and purchased a wolf, a goat, and a cabbage. On his way home, the farmer came to the bank of a river and rented a boat. But crossing the river by boat, the farmer could carry only himself and a single one of his purchases: the wolf, the goat, or the cabbage.
If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage.
The farmer’s challenge was to carry himself and his purchases to the far bank of the river, leaving each purchase intact. How did he do it?
A few things must be acknowledged from the beginning. First of all, it must be an absolutely massive cabbage. Seriously? Can you not find a way to fit the cabbage onto the boat, along with the wolf or goat? Maybe the farmer would need to leave his boots or hat behind if the load was a bit too heavy, but still….
Secondly, either the wolf is really stupid, or he’s just biding his time. The fact that a goat and/or man is present is hardly much of a deterrent if the wolf decides he wants to chow down on any available meat products.
Thirdly, if the wolf is so dangerous, why the heck did the farmer buy him in the first place? Last we checked, wolves weren’t exactly in the top ten of farmers’ favorite livestock to raise. Is the farmer supposed to stay awake all night to keep the wolf from getting to the goat? Let’s think this through, people!
OK, all of that aside, let’s get back to the main point: how would you solve the farmer’s dilemma? (We’re talking about the original puzzle of course. Solving the problem of the farmer’s insistence on keeping the wolf around is going to take a team of therapists and a lot more time than you have available at the moment.)
Give it some thought, and then scroll down to see if you got it right.
1. Take the goat over, leaving the meat-eating wolf safely alone with the cabbage.
2. Return, leaving the goat safely by himself on the other side.
3. Load up the cabbage.
4. Take the cabbage to the other side, leaving the wolf by himself.
5. Load up the goat to join you on the return journey, leaving the cabbage safely by itself on the other side.
6. Return and drop off the goat, replacing him on the boat with the wolf.
7. Take the wolf to the other side, leaving the goat by himself, praying the whole time that the wolf doesn’t realize that there’s no way you can stop him from devouring you and ripping the flesh off of your bones.
8. Leave the wolf safely with the cabbage.
9. Return and pick up the goat.
10. Take the goat to the other side.
How did you do?