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23 votes
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Protagoras's Paradox. An Unsolved Court Case

There is no paradox. The teacher should get paid, one way or another. The key to understanding the situation is realizing there are multiple slightly different scenarios that are all being described ...
Rob Watts's user avatar
  • 5,976
21 votes

Plant 9 trees in 10 rows of 3

I think there might be quite a lot of possible answers, but here is one of them: EDIT: I think there might be quite a lot of possible answers, but here is one of them Let's rephrase that to: "I ...
Kevin Cruijssen's user avatar
17 votes

Plant 9 trees in 10 rows of 3

Legend: 1..9 are the trees. X = empty space. Solution 1: Lines: picture: Solution 2 (built with my awesome ms paint skills): Lines:
Marius's user avatar
  • 18.2k
15 votes

Plant 9 trees in 10 rows of 3

I've completely rewritten this post to hopefully be more coherent. The geometric puzzle suggests a related combinatorial puzzle: Given nine objects, how many non-isomorphic collections are there ...
Paul Sinclair's user avatar
12 votes

A ship departs from Le Havre

Well, I'm a bit confused but I'd say With the following reasoning
Hugh Meyers's user avatar
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12 votes
Accepted

What's the origin of the story about the inheritance of 17 animals in certain fractional parts?

There is an article by one Pierre Ageron entitled "Le partage des dix-sept chameaux et autres exploits arithmétiques attribués à l'imâm ˁAlî. Mouvance et circulation de récits de la tradition ...
Gareth McCaughan's user avatar
11 votes

Protagoras's Paradox. An Unsolved Court Case

Case 1. Case 2. Bonus: [EDIT] To answer the question about who's right and wrong...
Marius's user avatar
  • 18.2k
11 votes
Accepted

A Chess Puzzle With a Twist

The twist is that: Now the sequence of white moves is: It can be interrupted by In that case white needs one extra move:
Bolo's user avatar
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8 votes
Accepted

Plant 9 trees in 10 rows of 3

A third solution. I've been searching systematically for them (I've eliminated all the combinatorial solutions other than ABC, A14, A25, A36, B15, B26, B34, C16, C24, C35 - it is the only one with ...
Paul Sinclair's user avatar
8 votes
Accepted

Edward and Bruce

Edward and Bruce After spending quite a while researching Robert the Bruce, his younger brother Edward Bruce, and other related historical figures, I hit upon the idea of considering Turning my back ...
Rand al'Thor's user avatar
7 votes

Protagoras's Paradox. An Unsolved Court Case

The student wins the case and then has to pay back the fee. The claim being made is against a future call: "I will pay you one day"--well there's no actual way to prove that the student failed to ...
Tommy's user avatar
  • 71
7 votes
Accepted

History of "Bulls and Cows"

According to codebreaker-mastermind-superhirn.blogspot.co.uk The exact year when the number guessing game Bulls and Cows was invented is not known. "Bulls and Cows has been played as a paper-and-...
Jonathan Allan's user avatar
6 votes

Protagoras's Paradox. An Unsolved Court Case

This doesn't seem to be that difficult.
Terry Lewis's user avatar
6 votes

What kind of glues are not conducive to long-term puzzle preservation?

I have solved Ravensburger's Neuschwanstein castle (5000 pcs) some ten years ago. It has an impressive size of 153 x 101 cm (see details on 5000 pcs puzzles). Once the puzzle was solved, I used this ...
Matsmath's user avatar
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6 votes
Accepted

A ship departs from Le Havre

How many Le Havre-bound ships will the New York-bound vessel meet, with today as its date of departure? Reason:
Kevin Cruijssen's user avatar
6 votes

A ship departs from Le Havre

Answer: Assumptions: A one-way journey takes exactly 7 x 24 hours. The ships leave at noon, local time. The ships leave at the first noon that takes place after arriving. Reasoning; EDIT: The ...
MichaelK's user avatar
  • 709
6 votes

Source of: Two Doors with Two Guards - 1 lies 1 tells the truth riddle?

The common name for such types of puzzles is a Knights and Knaves puzzle (named by Raymond Smullyan in a book from 1978) or just a liars puzzle. The earliest I've found is Mathematical Recreations (...
qwertyu63's user avatar
  • 3,929
5 votes

A ship departs from Le Havre

Answer: Because
Alessandro's user avatar
5 votes
Accepted

Puzzle that consists of all possible combinations of pieces containing 5 squares

They are called pentominoes. Because dominoes are 2 squares joined together, pieces made from more squares were dubbed trominoes, tetrominoes, pentominoes, hexominoes, etc. Wikipedia article on ...
Jaap Scherphuis's user avatar
5 votes
Accepted

Copycat Chess, Again

Attempt 2: https://lichess.org/editor/rn3b1r/p1ppnppp/bp2kq2/8/3pP3/BP2KQ2/P1PP1PPP/RN3B1R_w_-_- It should be mentioned that: Update from El-Guest (you can delete this if you want, I just wanted to ...
Elder's user avatar
  • 76
5 votes

Find the result of this dual key cipher

The results for both puzzles are: and an incomplete one: The cipher is a variant of: But: A note for the alphabets:
athin's user avatar
  • 34.2k
5 votes
Accepted

Were the Decipher II and Decipher III puzzles solved, and if so when and by whom?

Two videos have been made that investigate this topic in detail and explain who won each. The first video about the Decipher puzzles has a good background. https://www.youtube.com/watch?v=meaUE2b5whI ...
John's user avatar
  • 166
4 votes

When and where was the first logic-grid-based puzzle published?

The sort of logic puzzles James Jenkins refers to involve n-valued logic where n is always at least 3, and, in my experience, almost always at least 4. The grid in James Jenkins's OP is for a problem ...
Rosie F's user avatar
  • 8,640
4 votes

A ship departs from Le Havre

The answer is: Because As further proof of this: Yay, lateral thinking. But this is what would probably happen in reality.
Darrel Hoffman's user avatar
4 votes

A Chess Puzzle With a Twist

Oh, please no. So, if White plays and then or he will always win.
BaSzAt's user avatar
  • 5,667
4 votes

A ship departs from Le Havre

Naive answer Taking into account both ends Taking into account time zones
Trenin's user avatar
  • 8,974
4 votes

A ship departs from Le Havre

Answer: Reasoning: Generalisation:
Roby5's user avatar
  • 1,948
4 votes

Labyrinthus Londoninensis, or The Equestrian Perplexed

The red path in this image appears to me to work. The blobby grey bits are my scribblings to help clarify some impassable or pointless routes.
Gareth McCaughan's user avatar
4 votes

Was "Crook's algorithm" for Sudoku really only developed in the 21st century?

Modern Sudoku was only invented around 1979, and not widespread for another 10+ years. Source: Sudoku on Wikipedia Had the algorithms been developed immediately after Sudoku became widespread, it ...
Herb's user avatar
  • 3,333
3 votes

Protagoras's Paradox. An Unsolved Court Case

I'm not sure this is as much of a fallacy as anyone would like to think it is. It relies essentially on personality traits of these two parties and the hypothetical society in which they live. ...
pay's user avatar
  • 131

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