Questions tagged [river-crossing]

For questions regarding how to get items or people across something obeying a set of rules.

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10
votes
2answers
165 views

Missing lattes and mutually mistrustful words

It's always amusing to watch two kids who don't trust each other swap baseball cards by exchanging them at exactly the same moment. Words can be equally mistrustful about trading their letters. ...
3
votes
2answers
533 views

Boat children and army crossing the river puzzle

During the war, a small detachment found itself confronted by a deep and wide river. However, they found a small boat in which two-children were rowing about. It was a very small boat and can only ...
11
votes
1answer
210 views

Don't look back, crazy clown

Start with these two words INSANE RETROSPECT and see if you can get them to exchange places by transferring one letter at a time. With each ...
5
votes
1answer
198 views

Uncover Lenny Fingers' street hustle

Lenny Fingers is out on the street again, hustling people with his shell games. This time, he's using words. As you walk by, Lenny grabs you with an enthusiastic smile and shows you two words side-...
33
votes
2answers
3k views

The cat exchanges places with a drawing of the cat

Given CAT RENDERING see if you can get them to exchange places, resulting in RENDERING CAT by ...
20
votes
1answer
1k views

Farmer needs to get his word across the river

In the spirit of the classic river-crossing puzzles: ...
2
votes
1answer
204 views

Rigorous way to solve the river crossing problem

I encountered this classic brain teaser: Four people, A, B, C and D need to get across a river. The only way to cross the river is by an old bridge, which holds at most 2 people at a time. ...
12
votes
10answers
2k views

Another river with some extra letters

2 men are at a river. There is a boat. It holds only one person at a time. They both cross the river and continue their way... How? P.S. No Uber, helicopters, bridges, ropes, or anything else close ...
17
votes
2answers
903 views

numbers want to cross a river, but their sum must be a square number

In the world of numbers, numbers 1 to 9 want to cross a river, They have a boat which can take 1 to 3 numbers, But sum of the numbers must be a square number. The boat can not sail back itself, so ...
20
votes
7answers
3k views

Ali Baba and the 10 thieves

EDIT: This puzzle originates from the "International Mathematics Tournament of the Towns", and was published in the book "S.M.A.R.T circle overview" by Professor Andy Liu. The author has (albeit a ...
2
votes
1answer
935 views

3 cannibals and 3 missionaries on different side of the river

Three missionaries on the left side of a river and three cannibals on the right side of the river want to cross a river using a boat which can carry at most two people, The boat is on the cannibals ...
4
votes
2answers
2k views

When do missionaries and cannibals problems have solutions?

In the Missionaries and Cannibals problem: Three missionaries and three cannibals must cross a river using a boat which can carry at most two people, under the constraint that, for both banks, ...
6
votes
3answers
1k views

Zombie horde incoming! [duplicate]

Here is a puzzle I found on youtube and found quite fun to solve. You and 3 more people are for some reason running away from a horde of zombies in the darkness while holding a lantern. Suddenly, ...
7
votes
2answers
914 views

Cross the river with a small (4 spaces) boat

Giant, Slimy, Boy, Romy and Fatty want to cross a river. To cross the river there is a small boat. The boat only has 4 spaces. Every one can row the boat. At the boat, Giant needs 4 spaces. Slimy ...
6
votes
5answers
6k views

River Crossing Puzzle

There is a family which contains 4 members: Dad, Mom, Son, Daughter. They have a boat which carries only 100 kg at a time. Mom and Dad weigh 100 kg each, while Son and Daughter weigh 50 kg each. ...
8
votes
4answers
6k views

Quick!!! You got only 30 seconds

There are two checkpoints on a road namely Pt. A and Pt. B. There are 5 persons standing at the Pt. A namely P , Q , R , S, T. They have a car such that P , Q , R , S , T can travel to Pt. B in 1 , 3 ,...
-4
votes
1answer
177 views

Ancient mysteries of the Arab world [duplicate]

If we want to convey the lion and the sheep and feed from the bank of the river to the other how to do it? and the lion will not eat the sheep and the sheep will not eat the feed
-2
votes
2answers
722 views

Bridge's riddle [duplicate]

You're in a group of people going for an internship in a remote mountain lab. By mistake you pulled a lever with a skull just out of curiosity and it released some zombies. So you and your group had ...
2
votes
2answers
490 views

Crossing The River (Humans And Monsters Puzzle With A Twist)

3 couples on one side of a river. Aa Bb Cc (caps representing husbands, lowercase representing wives) One boat in which 2 people can travel at a time. At least one person must row the boat wherever ...
8
votes
2answers
780 views

Numbers nonexistent

This problem is one of the hardest problems I have ever encountered. If you don't trust links, here it is: There are some Couples wanting to cross a river by a boat. The boat can carry at most 3 ...
-1
votes
1answer
10k views

A man, a chicken, and a fox? [duplicate]

A man lives in a small house with a farm as his back garden and has a river beside his house. On the other side of the river is a shop. One day, he visited the shop, he bought a chicken and a fox for ...
6
votes
4answers
4k views

Can you solve this Bruce Wayne logic puzzle?

This variation of the classical Farmer Goat puzzle was in a puzzle contest at my college two years ago. Here it goes. Mr. Bruce Wayne is very fond of parties. Well, he’s more fond of girls, but, ...
4
votes
5answers
16k views

How can the animals get across the river without a fight breaking out?

There are three dogs and three cats that have to be transported across a river: a big dog, a medium dog and a small dog, a big cat, a medium cat, and a small cat. Rules: The raft can carry two ...
2
votes
2answers
3k views

The case of the 4 campers and the rickety bridge! [duplicate]

Four people need to cross a rickety rope bridge to get back to their camp at night. Unfortunately, they only have one flashlight and it only has enough battery left for seventeen minutes. The bridge ...
9
votes
3answers
3k views

$n$ couples crossing a river

There are $n$ couples on one side of the river. Nobody is on the other side. They have a boat that accommodates up to 2 people. For every trip across, someone(s) must bring the boat back as well. The ...
4
votes
3answers
410 views

$n$ monsters and $n$ people

There are $n$ monsters (M) and $n$ people (P) on the left side of a river. Nobody is on the right. They have a boat that can hold up to 2 beings. At no point on time may either of these be true: $$M_{...
-4
votes
1answer
2k views

How can the man get across the river with the two animals and the cabbage? [duplicate]

A man has a wolf, a goat, and a cabbage. He must cross a river with the two animals and the cabbage. There is a small rowing boat, in which he can take only one thing with him at a time. If, however, ...
-1
votes
1answer
636 views

A Fox, a Chicken, a Pile of Seeds, and a Boat [duplicate]

There's 2 islands, 1 island has a pile of seeds, a chicken, and a fox. There's also a boat next to this island, you have to get it all across with minimum uses of the boat. You can only take one ...
15
votes
1answer
5k views

Fastest way to cross a river: four people with different rowing speeds

This problem is commonly cited as a Microsoft interview problem, although I have paraphrased it here to involve a river and a boat instead of a bridge and a flashlight, and tweaked the crossing times ...
15
votes
4answers
30k views

Strategy to solve the Missionaries and Cannibals problem

In the Missionaries and Cannibals problem: Three missionaries and three cannibals must cross a river using a boat which can carry at most two people, under the constraint that, for both banks and ...
11
votes
2answers
560 views

What is the maximum number of items in a river crossing puzzle?

A River Crossing puzzle puts limits on the number of items that may cross a boundary, with limits on what may be left together. The "Fox, goose and bag of beans" is one of the earliest examples. Of ...
27
votes
4answers
17k views

Learning to Solve a River Crossing Puzzle

I have seen many variations of the following puzzle: Once upon a time, a farmer went to the market and purchased a fox, a goose, and a bag of beans. On his way home, the farmer came to the bank of ...