# Questions tagged [logical-deduction]

A puzzle that requires formal logical deduction to arrive at the solution. This suggests more than merely reasoning through clues to find an answer (you might want [situation] for that).

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### Help to solve Star Battle puzzle

I've solved a number of Star Battle puzzles, but once in a while some of them seem much harder than others. This has also been noted earlier here. It seems as if I'm missing some technique to be able ...
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### Empty suguru (tectonic) puzzle

Suguru (also knows as Number Blocks or Tectonic), is a popular type of grid-deduction puzzle: In a rectangular grid of squares, the squares are grouped into blocks. As with a sudoku, some squares ...
• 1,188
1 vote
367 views

### There is a method to these equations

Please find the method used to get these equations and solve the last one. The answer is a positive integer.
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### In logic puzzles, can I rely on "or" to mean "exclusive or"?

Is there a common rule for logic puzzles on whether the word "or" should be treated as inclusive or exclusive? In computers, "or" is always inclusive. In common speech, it seems ...
• 31
1 vote
83 views

### Is the puzzle presented below solvable with the information presented? [duplicate]

Is this puzzle, as presented, solvable by the average player, with only the information included below? If not, what would need to be added/changed/outtaken to make it more logical and cohesive (but ...
• 181
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### PSE Advent Calendar 2022 (Day 6): Christmas and Squares

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous DoorNext Door > Today's door ...
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This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous DoorNext Door > 'Twas the ...
• 5,613
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### PSE Advent Calendar 2022 (Day 2): Santa’s Magic Knapsack

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > Have you ...
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### PSE Advent Calendar 2022 (Day 1): A festive Sudoku

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.Next Door > Rules: Normal Sudoku rules ...
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### A logician's Bingo

Mark some cells on the following Bingo board, so that all statements in marked cells are true AND all statements in unmarked cells are false. A Bingo here is a set of five marked cells in a row, ...
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### 0hn0: is this correct deduction?

Starting with: Text: .....9..6 ....3.2.. 6.5....2. .7.6..R.. ...7R.... ..R.R.6.. 5.....5.. ..4..2... .9...1.1. We soon get to this: Text: ...
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### Walter’s wonky watch

Walter sticks to a strict schedule each weekday. He pays close attention to his digital watch, but it's not an ordinary watch. Here is his typical day in order: Each morning at sun, his alarm goes ...
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1 vote
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### Does "The investigator traveled the same week as the thief." in a logic-grid clue mean that two different people are referred to?

I've always wanted to know if a certain thing was expressly allowed or disallowed in logic puzzles. Here's a specific example: The investigator traveled the same week as the thief. Does this mean ...
• 31
1 vote
339 views

### 4 chest logic puzzle sequel to my old one finally!

There are 4 chests: Left, middle 1, middle 2 and right. One contains treasure whilst the other 3 contain a poisonous gas. Left opens if a true statement is said, right opens if a false statement is ...
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### What number did the game show host choose?

A game show picks a number from 1 to 100. You can send the host a list of "yes" or "no" questions. As an example, one of the questions can be "Is the number odd?". The ...
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### Find the carpets

This room has been filled with carpets, thirty of them. Each has a number inside precisely equal to its area. Find the carpets!
1 vote
273 views

### A Possible Solution to George Boolos' "The Hardest Logic Puzzle Ever"

The full explanation of the puzzle, by George Boolos, can be found here. Basically, it goes as follows: Three gods A, B, and C are called, in no particular order, True, False, and Random. True always ...
• 11
681 views

### The Fourth Hardest Logic Puzzle Ever

This is a beautiful variant of "The Hardest Logic Puzzle Ever". I learned it in high school math class a while ago. (I do not know if my teacher invented this variant.) I know the solution ...
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### Chain Puzzle: Video Games #02 - Fish Is You

This is the second Chain Puzzle in the Video Games series, in which all puzzles are themed around video games of all genres. The answer to this puzzle is a thematic word or phrase. The solver whose ...
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### Tile and Error - When Seven Ate Nine

Ok folks, so the three overlapping ellipses form seven curved regions. Your job is to place all seven tiles so that each region has exactly one tile and each ellipse adheres to the corresponding ...
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### This new puzzle type needs a name {7}

This puzzle is part of the Monthly Topic Challenge #5: On-and-onograms - and also extends the 'This new puzzle type needs a name' series... I believe I have invented a new type of puzzle... What is ...
• 134k
1 vote
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### Mastermind algorithm but for unique colors only

I have seen Donald Knuth's Algorithm to guess the correct pattern in maximum 5 tries. However, I want to write a program to find the correct pattern effectively however the code maker can only make a ...
431 views

### Stuck on hard Kakuro

I‘m stuck on this Kakuro. Does anyone have any hints how to proceed? Thanks!
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### find the next pattern [duplicate]

What will be the next pattern? Why... thanks.
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### Question about a minorly used tag

There once were sixteen chairs. Next to orthogonal. There are people wearing only black or only white. [REDACTED] A black-wearer is in the corner. A white-wearer is next to a black-wearer. At least ...
493 views

### Crossword by name, crossword by nature

This puzzle is part of the Monthly Topic Challenge #4: Cross-*non*-words Here's a crossword puzzle - in fact, here are two of them - with a twist. Every entry in the two grids below contains the 5-...
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### Polybius cipher meets Grid Puzzle

Here is a puzzle I've been trying to solve for a week, but I've not made any real progress. Some of the things I've tried I will include as spoilers. The puzzle is from a competition which has just ...
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### Snakes, Ladders and Magic Dice

This is a great Puzzle recently I made. A Wizard has captured 2 friends A and B in a Magical land with Snakes and Ladders in different rooms. There are a total of 100 rooms. The Wizard gives both of ...
254 views

### Cow Training Farm

Other than ordinary farms like Animal Farm, there is a farm called 'Cows Training Farm', which is a farm that trains $15$ very orz cows. Each year, six cows are chosen to join a competition. Mason is ...
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### What is the missing number in this wheel?

What's the missing number? From World of Engineering.
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### The Universe's Secret

To find the universe's secret, first solve the Sudoku variant with #s 1-7 only. No number may be repeated on any diagonal. No numbers go in the squares with red or green dots. Then use the solution ...
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### Which gnome is the tallest?

This is a riddle I and some friends came up with. Say I have four gnomes with different heights. They state the following: Gnome 1: I am the shortest. Gnome 2: I am neither the tallest nor the ...
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### My Master Piece Logic Puzzle Mystery

Six suspects for a bank robbery line up in front of you, with different nationalities, activities, occupations, suit colours and items. They all look nondescript to you, but you know someone holds a ...
358 views

### Prisoners, apples & oranges - revisited

You are one of twelve prisoners, and the warden has a game to play with you. In a room, there are twelve boxes, four of them contain two apples, four contain two oranges, and the rest one of each, but ...
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### Prisoners, apples & oranges

You are in a group of sixty prisoners, and the warden has a game to play with you. In a room there are sixty boxes. Each box can contain either two apples, two oranges or one of each, but you don't ...
• 557
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### Sudoku pairs diagonal corners

Is it correct to deduct that the [4,8] (blue) pairs in diagonal corners, project [4,8] on the opposite (green) corners, such that the other values (1 and 6) could be eliminated? (*) I'm not sure if ...
• 123
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### 5×5 sudoku with special properties

Complete the network with numbers from 1 to 5 so that the same number does not occur in any line, column, specially marked figure and on both diagonals. I tried to start with a number that I know for ...
• 265
399 views

### Tentai Show: Unlikely travels

My friend loves telling me her increasingly outlandish travel stories but I think this time she's gone a little too far and I'm not buying it. Can you tell which faraway land she wants me to think she ...
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### A curious incident [duplicate]

You are a detective and have been for the past 20 years. Pretty experienced if you think about it. One day you were at your office when suddenly the telephone rang. It was your assistant. Tring!!!! ...
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### - Pandora's Box -

After Prometheus had stolen fire from heaven and bestowed it upon mortals, Zeus, the king of the gods, determined to counteract this blessing. Zeus commissioned Hephaestus, the god of fire, to fashion ...
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### Changing either an actor or an actress

About After the completion of this table, each row will have an actor and an actress who acted together in a movie directed by the director in that row. Rule While moving from the first row to the ...
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### logical deduction - Persian Rugs - A Zebra Puzzle (Einstein's Riddle) Variation

You can play this Zebra Puzzle here: https://www.brainzilla.com/logic/zebra/persian-rugs/ Client #1 Client #2 Client #3 Client #4 Client #5 color name type symbols price place Five men, who ...
416 views

### Italian Exhibition - A Zebra Puzzle (Einstein's Riddle) Variation

You can play this Zebra Puzzle here: https://www.brainzilla.com/logic/zebra/italian-exhibition/ Woman #1 Woman #2 Woman #3 Woman #4 Woman #5 shirt name surname painter time age Five women are ...
362 views

### Possible parity for sliding puzzle

As you can see, I have a sliding 5x5 puzzle, but no matter what way I scramble it and solve it again, I always seem to have two pieces that need to be swapped. Is there a way to swap the two pieces? (...
315 views

This is a Heyacrazy* puzzle. The rules are as follows: Shade in some cells in the grid. Two shaded cells cannot share an edge, and all unshaded cells must be orthogonally connected. Once finished, it ...
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While walking through the forest, on the way to confess to your crush, you come upon an old house. Outside of this house is an old, damaged Brazen Head, with a hastily wired coin-slot appended beside ...
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### How many solutions in this Statue Park (Loop)?

Rules of Statue Park (Loop), from GM Puzzles Place each of the twelve pentominoes into the grid once, with rotations and reflections allowed. No two pentominoes can overlap or be orthogonally ...
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### This new puzzle type needs a name {OVERLAPPED EDITION}

This is my contribution to the 'This new puzzle type needs a name' series, started by @Stiv. I believe I have invented a new type of puzzle... What is its name? Penpa+ link A little advice.. Even ...
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### Stitches solution and tips

I've lately played a lot of "Stitches" puzzle game on this site. Slowly going on harder ones, I'm now stuck on a "10x10/3÷ Hard Stitches" puzzle (see screenshots below). I can't ...
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1 vote