River Crossing Puzzle: Fox, Chicken and Corn Solution
The river crossing puzzle fox chicken corn solution takes 7 crossings: take the chicken over, come back alone, take the fox over, bring the chicken back, take the corn over, come back alone, then take the chicken over again. The whole trick is realizing you're allowed to carry something backward. The fox never gets left with the chicken, and the chicken never gets left with the corn.
If puzzles where you have to plan several moves ahead fry your brain, IQ Tester shows whether logic or working memory is the weak link and drills it: Find my weak spots.
The classic puzzle
A farmer needs to get a fox, a chicken and a bag of corn across a river. His boat is tiny: it fits the farmer plus one item.
The rules:
- If the fox is left alone with the chicken, the fox eats the chicken.
- If the chicken is left alone with the corn, the chicken eats the corn.
- The fox doesn't eat corn. (Relatable.)
- While the farmer is there, nobody eats anything.
How does he get everything across safely?
You'll also see this as the fox, chicken and grain riddle, or the wolf, goat and cabbage puzzle. Same logic, different cast. It's one of the oldest puzzles around: versions appear in a collection of math problems associated with the medieval scholar Alcuin of York.
The 7-crossing solution
Here's the river crossing puzzle answer, step by step. "Start" is the side they begin on; "Far" is where they're going.
| Trip | Farmer takes | Start bank | Far bank |
|---|---|---|---|
| 1 | Chicken → | Fox, Corn | Chicken |
| 2 | Nothing ← | Fox, Corn | Chicken |
| 3 | Fox → | Corn | Fox, Chicken |
| 4 | Chicken ← | Chicken, Corn | Fox |
| 5 | Corn → | Chicken | Fox, Corn |
| 6 | Nothing ← | Chicken | Fox, Corn |
| 7 | Chicken → | (empty) | Fox, Chicken, Corn |
Seven crossings, nothing eaten. (You can also swap fox and corn in trips 3 and 5, which works just as well.)
Why the chicken goes back
This is the step that breaks people. Most of us assume every trip should move things forward. Bringing the chicken back feels like undoing progress.
Here's why it's forced:
- The chicken is the problem child. It clashes with both the fox and the corn. The fox and corn are fine together.
- So the chicken has to go first. Taking the fox leaves chicken + corn (corn gets eaten). Taking the corn leaves fox + chicken (chicken gets eaten).
- On trip 3, something has to join the chicken. Whatever you bring (fox or corn) will clash with it the moment you leave.
- The only fix: swap. Drop off the new item, pick the chicken up, bring it back.
Lesson for every hard puzzle, exam question and group project: sometimes the move that looks like going backward is the only way forward.
Harder versions: wolf-goat, couples, missionaries
Once you've got the fox chicken river puzzle, level up.
Missionaries and cannibals
Three missionaries and three cannibals need to cross. The boat holds two people and can't cross empty. On either bank, if cannibals ever outnumber missionaries (and there's at least one missionary there), bad things happen.
Solution (11 crossings), where M = missionary and C = cannibal:
- 2C cross.
- 1C returns.
- 2C cross.
- 1C returns.
- 2M cross.
- 1M + 1C return.
- 2M cross.
- 1C returns.
- 2C cross.
- 1C returns.
- 2C cross.
Check any step: missionaries are never outnumbered on either bank.
Jealous couples (river crossing puzzle 3 couples)
Three couples, a boat for two. The rule in the classic version: no partner can be on a bank or in the boat with someone else's partner unless their own partner is there too. It has the same shape as missionaries and cannibals and also takes 11 crossings. Try it with coins or sticky notes before searching the answer.
The bridge and torch problem
Not a river, but same family. Four people must cross a bridge at night with one torch (flashlight). Max two on the bridge at once, and the torch must be carried every trip. They take 1, 2, 5 and 10 minutes; a pair moves at the slower person's speed. Can they all cross in 17 minutes?
Answer: 1 and 2 cross (2 min). 1 returns (1). 5 and 10 cross (10). 2 returns (2). 1 and 2 cross (2). Total: 17 minutes. The trick: send the two slowest together so you only pay the 10 once.
The river crossing puzzle with prisoner (the family one)
You may have played a river crossing puzzle game online with a family, a police officer and a prisoner (or thief), where the prisoner can't be left with family members without the officer, and only certain people can drive the raft. It's a bigger version of the same idea, and the next trick is how you solve it without trial and error.
Here's where doing it alone gets hard: holding who's on which bank, what's safe and what you've already tried, all in your head. That's working memory and logic under load. IQ Tester's untimed logic and pattern questions show which of those is your weaker link, and its guides give you a short daily drill for it. Find my weak spots
The state-diagram trick for any crossing puzzle
This is how to solve river crossing puzzles without guessing. Computer science students use the same idea for search problems.
- Define a state. Write down who's on the start bank and where the boat is. Everything else is on the far bank. Example: "Fox, Chicken, Corn, Farmer | boat at start."
- List every legal move from that state (what can the boat carry?).
- Throw out illegal states (anyone eaten, outnumbered, etc.).
- Throw out states you've already visited. No going in circles.
- Repeat until you reach "everyone on the far bank."
Draw each state as a box and each move as an arrow. For the fox-chicken-corn puzzle, you'll see only a handful of safe states exist, and the path through them is basically forced. For missionaries and cannibals, the diagram reveals why step 6 (sending one of each back) is the key move.
It works on anything: river crossings, logic grids like the Einstein riddle, even planning your week.
Challenge your mates
Turn it into a group-chat or class challenge:
- Round 1: Fox, chicken, corn. Timer on. Most people get it in a few minutes once they think of bringing something back.
- Round 2: Bridge and torch. Most people's first try is 19 minutes (the fastest person escorts everyone). Who finds 17?
- Round 3: Missionaries and cannibals with coins on a desk.
Want more brain-benders? Try lateral thinking puzzles for teens, where the answer comes from reframing the story, not planning moves.
Level up the planning skill behind every crossing
The river crossing puzzle fox chicken corn solution is 7 trips, and the secret is the backward move with the chicken. If multi-step planning is where you get stuck, it's worth knowing why. IQ Tester's 20 untimed questions give you a free score band and three of your four reasoning strengths in minutes, and its guides turn your weakest area into a short daily drill.
FAQ
What is the answer to the fox, chicken and corn riddle?
Take the chicken across, return alone, take the fox across, bring the chicken back, take the corn across, return alone, then take the chicken across. That's 7 crossings and nothing gets eaten.
Is the wolf, goat and cabbage puzzle the same as fox, chicken and corn?
Yes. The wolf is the fox, the goat is the chicken and the cabbage is the corn. The goat, like the chicken, is the one that clashes with both others, so it goes first and comes back once.
How many crossings does missionaries and cannibals take?
The classic version with three of each and a two-person boat takes 11 crossings. The key move is sending one missionary and one cannibal back together in the middle.
What's the trick to solving any river crossing puzzle?
Write each situation as a "state" (who's on which bank and where the boat is), list the legal moves, cut the unsafe or repeated states, and follow the path to the goal. It turns guessing into a map.
Are river crossing puzzles used in IQ tests?
Planning puzzles like these test logical reasoning and working memory, which many reasoning tests measure. They aren't a standard IQ test item, but they're great practice for thinking several steps ahead.