River Crossing Puzzles With Answers
Updated · Best Riddles With Answers editorial team
Quick answer: This page has 42 river crossing puzzles with answers, from simple boat counts to the wolf, goat and cabbage classic, torch and bridge puzzles, and weight limits. It suits puzzle fans, teachers and parents. Every puzzle has a valid solution, and the answer gives the exact sequence of moves so you can check it step by step.
Easy River Crossing Puzzles
A boy's boat holds him and one animal. He has a cat and a dog that get along fine. What is the fewest one-way crossings to get both animals across?
3: take the cat over, come back alone, take the dog over.
A boat holds two people, and someone must row it back each time. How many one-way trips does it take to get 3 people across?
3: two cross, one rows back, then two cross.
A man must carry 3 sacks of potatoes across a river in a boat that holds him and one sack. How many one-way crossings does he need?
5: over with a sack, back, over with a sack, back, over with the last sack.
A man has 4 parcels and a boat that holds him and two parcels. How many one-way crossings does he need?
3: over with two parcels, back alone, over with the other two.
Four friends have a boat that holds two, and one of them must row it back each time. How many one-way trips do they need?
5: two over, one back, two over, one back, two over.
Seven hikers have a boat that holds four, and someone must row it back each time. How many one-way trips do they need?
3: four cross, one rows back, and then the four who are left cross.
A ferry carries 5 cars at a time. There are 12 cars waiting. Counting the empty trips back, how many one-way crossings does it take to move them all?
5: loads of 5, 5 and 2 make 3 crossings over, plus 2 empty trips back.
A river has 7 stepping stones in a row. How many steps does it take to hop from one bank to the other, one stone at a time?
8: bank to stone 1, then 6 more hops, then the last stone to the far bank.
An adult weighs 80 kg and two children weigh 40 kg each. The boat holds at most 80 kg and anyone can row. How do all three cross?
5 crossings: both children over, one child back, adult over, the other child back, both children over.
Ann takes 3 minutes to cross a bridge and Ben takes 5. They cross together, holding hands, at the slower pace. How long does it take?
5 minutes, the slower person's time.
A ferry leaves the north bank, makes 3 full round trips and then one more single trip. On which bank does it end, and how many one-way crossings did it make?
The south bank, after 7 crossings (6 for the round trips plus 1).
A boat holds only one person. Three people must cross, and each can row. How many one-way trips do they need?
5: over, back, over, back, over.
Trickier River Crossing Puzzles
A farmer has a wolf, a goat and a cabbage. His boat holds him and one item. The wolf eats the goat and the goat eats the cabbage if left alone. How does he cross?
7 crossings: goat over; back alone; wolf over; goat back; cabbage over; back alone; goat over.
Two married couples must cross in a boat for two. A wife must never be with the other couple's husband unless her own husband is also there. How do they cross?
5 crossings: both wives over; one wife back; both husbands over; the wife on the far bank back; both wives over.
Three people cross a bridge at night with one torch. At most two cross at a time, at the slower pace. They take 1, 2 and 5 minutes. What is the quickest total time?
8 minutes: 1 and 2 cross (2), 1 returns (1), 1 and 5 cross (5).
Four people with one torch cross a bridge, two at a time at the slower pace. They take 1, 2, 5 and 8 minutes. What is the fastest total?
15 minutes: 1 and 2 cross (2), 1 back (1), 5 and 8 cross (8), 2 back (2), 1 and 2 cross (2).
Four people with one torch cross a bridge, two at a time at the slower pace. They take 1, 3, 4 and 5 minutes. What is the fastest total?
14 minutes: 1 escorts each person. 1 and 5 (5), 1 back (1), 1 and 4 (4), 1 back (1), 1 and 3 (3).
Anna weighs 50 kg, Ben 60 kg and their uncle 100 kg. The boat carries at most 110 kg and anyone can row. What is the fewest crossings?
5: Anna and Ben over, Anna back, uncle over, Ben back, Anna and Ben over.
A boat holds either one soldier or two boys, and any of them can row. How many one-way crossings do 3 soldiers and 2 boys need?
13. Each soldier takes 4 crossings (boys over, a boy back, soldier over, other boy back), then the boys cross: 3 x 4 + 1 = 13.
A boat holds 3 people and someone must row it back each time. How many one-way trips take 10 people across?
9: each round trip nets 2 people, so 4 round trips (8 trips) put 8 across, and a ninth trip takes the last 2.
A boat holds 3 people and someone must row it back each time. How many one-way trips take 9 people across?
7: three round trips move 6 people across and the final trip takes the last 3.
A ferry for 5 passengers must be rowed back by one passenger each time. How many one-way trips take 12 people across?
5: two round trips move 8 people across, then the final trip takes the last 4.
A man has 5 chickens and a boat that holds himself and two chickens. How many one-way crossings does he need?
5: two over, back alone, two over, back alone, one over.
A farmer has a wolf and two sheep, and a boat that holds him and one animal. The wolf eats any sheep it is left alone with. How does he cross?
7 crossings: wolf over; back alone; sheep A over; wolf back; sheep B over; back alone; wolf over.
Hard River Crossing Puzzles
Three rabbits and three foxes cross in a boat that holds two, and any can row. Where rabbits are present, foxes must never outnumber them on a bank. What is the shortest plan?
11 crossings. Foxes: 2 over, 1 back, 2 over, 1 back. Rabbits: 2 over, a rabbit and a fox back, 2 over, a fox back. Foxes: 2 over, 1 back, 2 over.
Five people with one torch cross a bridge, two at a time at the slower pace. They take 1, 2, 3, 4 and 5 minutes. What is the fastest total?
16 minutes: 1 and 2 (2), 1 back (1), 4 and 5 (5), 2 back (2), 1 and 2 (2), 1 back (1), 1 and 3 (3).
A boat holds either one soldier or two boys, and any of them can row. How many one-way crossings do 5 soldiers and 2 boys need?
21. Each soldier takes 4 crossings and the boys then cross together: 5 x 4 + 1 = 21.
Five people with one torch cross a bridge, two at a time at the slower pace. They take 1, 3, 6, 8 and 12 minutes. What is the fastest total?
29 minutes: 1 and 3 (3), 1 back (1), 8 and 12 (12), 3 back (3); then 1 and 3 (3), 1 back (1), 1 and 6 (6).
A boat holds 6 people and one must row it back each time. How many one-way trips take 20 people across?
7: each round trip moves 5 people across; three round trips move 15, and the final trip takes the last 5.
A boat holds 8 people and one must row it back each time. How many one-way trips take 100 people across?
29. Each round trip nets 7 people. 13 of them leave 9 behind, too many for one last trip of 8. So 14 round trips (28 trips) plus a final trip: 29.
A father weighs 90 kg, a mother 60 kg and two children 30 kg each. The boat carries 90 kg at most. What is the fewest crossings, and how?
7: children over, child back, father over, other child back, mother and a child over, that child back, both children over.
Two men each need to cross a river. There is one boat that holds only one person, yet both get across. How?
They start on opposite banks. One rows over, the other takes the boat back.
A river flows at 3 km/h. A boat travels at 5 km/h in still water. It rows 12 km upstream and then returns. How long does the round trip take?
7.5 hours: upstream speed is 5 - 3 = 2 km/h, so 6 hours; downstream is 8 km/h, so 1.5 hours.
Four people with one torch cross a bridge, two at a time at the slower pace. They take 2, 3, 8 and 9 minutes. What is the fastest total?
20 minutes: 2 and 3 (3), 2 back (2), 8 and 9 (9), 3 back (3), 2 and 3 (3).
Quick-Fire River Crossing Puzzles
The land on either side of a river.
Bank.
A small boat moved with oars.
Rowboat.
A shallow place where you can walk across.
Ford.
A flat boat that carries cars across water.
Ferry.
Flat rocks you hop across one at a time.
Stepping stones.
The place where a river meets the sea.
Mouth.
A structure that carries a road over water.
Bridge.
A float made of logs tied together.
Raft.
How to Solve River Crossing Puzzles
Most river crossing puzzles are solved by listing what is on each bank after every move. Write the near bank and far bank as two lists, check the rules for both lists, and look for a move that brings something back. Bringing a passenger back with you is often the key.
For counting puzzles, remember that someone must row back after every trip except the last. Each round trip moves one fewer person than the boat holds, and the final trip carries a full load. That pattern gives the answer without drawing every move.
Frequently Asked Questions
How do you solve the wolf, goat and cabbage puzzle?
Take the goat over first, return alone, take the wolf over, bring the goat back, take the cabbage over, return alone and take the goat over again. That is 7 crossings, the minimum.
What is the trick in most river crossing puzzles?
The trick is that you may bring an item or a person back across the river. It feels like going backwards, but it is often the only way to avoid leaving the wrong pair together.
How do you solve torch and bridge puzzles?
Send the two slowest people across together so their time is only counted once, and use the fastest people to carry the torch back. Compare the two main strategies and choose the shorter total.
Are these river crossing puzzles good for classrooms?
Yes. They teach planning, checking rules and working step by step. Younger pupils can use the counting puzzles with counters, while older students can try the torch puzzles and the weight limits.
