# 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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### PSE Advent Calendar 2023 (Day 11): Divide the cookies and milk

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2023. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > Santa’s ...
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### Another type of Sudoku puzzle

I just found a weird-looking sudoku I left years ago in my basement: I think there was a specific name for this type of puzzle, but I forgot to write it down and now I can't remember it! The only ...
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### What should be in box 4?

Box 1: April, June, September, November. Box 2: March. Box 3: January, May, July, August, December. What should be in box 4, and why?
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### PSE Advent Calendar 2023 (Day 9): The Peppermint Twist

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2023. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > This puzzle ...
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### What technique can be used to solve this 6x6 sudoku?

Which Sudoku technique can be used to solve this? The screenshot is from the open source Sudoku app by SECUSO (Security Usability Society) for the Android platform.
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### PSE Advent Calendar 2023 (Day 3): 24 dangerous doors

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2023. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > Task: Solve ...
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### What is the next logical step I can take when solving the Nov. 30 2023 Sudoku in the Wisconsin State Journal?

Note: sorry for posting this on Dec. 1, but don't worry, I haven't looked at the Sudoku solution yet. So today I decided to try to solve the Sudoku in the Wisconsin State Journal. Now, even though ...
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### Turn Back the Clocks

This is part 45 of the puzzle series Around the World in Many Days. Each part is solvable on its own. Dear Puzzling, This is a Slitherlink puzzle. Draw a single continuous loop along grid lines that ...
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### 160 foxes are stuck on an island with 1 chicken. Will the chicken be eaten? [duplicate]

An island is filled with apple trees and other plants. The only inhabitants are 160 foxes and 1 chicken. The foxes are smart, logical, and completely aware of their surroundings. They have two food ...
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### Is the "Challenging" Kenken in the Wisconsin State Journal from April 27 2021 solvable?

Note: The reason that I picked this one to self-answer was because it was a few weeks (months?) before the Wisconsin State Journal stopped printing Kenken puzzles. This was also the newest Kenken from ...
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### Filling in an 8x8 minesweeper grid with mines (Day 11: Christmas tree edition)

Previous puzzles Contains: Single mines (1 mine), Double mines (2 mines), Triple mines (3 mines) To get the $\color{green}✓$: Solve the Nonogram Solve the Minesweeper puzzle Note: partial answers ...
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### Sudoku variants #2: Lined Numbers (6x6 grid)

Previous variant Today's Sudoku variant is a bit weird. Here's why: Take this screenshot: From this, you might argue that there is nothing that can be logically deduced on this grid. Now you might ...
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### Filling in an 8x8 minesweeper grid with mines (Day 10: Double Neighbors)

Previous Minesweeper puzzles Based off of Day 10 of the Minesweeper Advent Calendar on heptaveegesimal.com Difficulty (approximate): ★★★★☆ Contains: Single mines (1 mine), Anti-mines (-1 mines), ...
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### Relatively prime numbers

Can you fill in the circles with numbers such that: Each pair of circles connected by one line contains relatively prime numbers Each pair of circles connected by two lines do not contain relatively ...
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### Another puzzle combination (feat. Kakuro)

Today, I am going to give you another puzzle combination. This time, it features a Kakuro! However, there are some things to note: There are only two puzzles that I have combined, although you have ...
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### A Hokuro, but with a twist!

Recently, I created my first Hokuro puzzle, which was received really well. However, this time, there is a twist! Not with the rules or anything, however, it is combined with a Nonogram! Luckily, the ...
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### A 6x6 table with nothing filled out?

So as you might or might not know, I can be quite evil sometimes, especially with my Hidato puzzles that contain no numbers. But, today, I decided to give you an enigmatic-puzzle! This means that you ...
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### Anyone up for a 3x3x3 Hidato?

So, I have been pretty evil with how I make Hidato puzzles lately, with there being no numbers. To make up for it, I have decided to make a 3x3x3 Hidato for you all. Yes you read that right. I made a ...
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### Press The Grue Button

[This puzzle is inspired by the webpage https://apparenthorizons.com/2017/10/12/the-grue-problem-and-deep-learning/] 55 workers have got a chance to double their pay, as said by their boss. So, the ...
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### How would I be able to solve this difficult Hidato?

So I was doing Hidato puzzles on the official Hidato site when I came across this puzzle that I am having trouble solving, and while I have been able to solve it partly, I don't think that I'm going ...
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### Equality-breaking function

There's a function that satisfies the following: $f(2) = 1, f(2^2) = 2, f(-3^3) = 3$ $f^n(x) = 3(n-1) + f(x)$ Where $f^n$ means $f$ composed with itself $n$ times. Lastly, $f$ is not equality ...
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### Minimum Races for Top 3 horses

There are 37 horses and 6 horses can race each time on a track. Find the fewest number of races required to get the top 3 fastest horses. Source - Glassdoor I know we can definitely do it in 9 races ...
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### A Hidato, but with no given numbers? #2: 5x5

Previous puzzle As you may or may not know, I can be a bit evil sometimes. Today, I am going to give you a 5x5 Hidato with no given numbers to start. However, this isn't a Mobius Strip puzzle like ...
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### A Hidato, but with no given numbers?

I can be a bit evil sometimes. Today, I am going to give you a Hidato with no numbers! It gets worse: This puzzle is on a Mobius Strip Y[1] However, I will give hints as to what the numbers are, so ...
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### A question from Bob to Bob

Set-up: John and Bob are playing a game that goes like this: Bob is alone in a completely opaque, featureless room. Bob chooses a question, though some types of questions are off-limits, which will ...
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### Feedback on a themed Nonogram/Hidato puzzle combo with a cell color gimmick

So, as you might know, the Christmas season is coming up. (17 days until Dec. 1 at the time of writing) I'm thinking of posting some Christmas-themed puzzles during that season, and just want some ...
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### A Hidato, but with a complex twist!

Today's Hidato puzzle has a pretty complex twist. What is the twist, you ask? This is what the twist is: There are three different colors: Yellow: Represents a prime number Green: Represents a ...
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### Double Choco: Snaking

Rules of Double Choco: Divide the grid into rooms along grid lines. Each room contains two halves: one orthogonally connected area of shaded cells and one orthogonally connected area of unshaded ...
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### My first puzzle combination: A Nonogram and Hidato

Today's puzzle is a bit strange. Why, you might ask? Because it is a Nonogram and a Hidato combined! Rules of Nonogram: The grid must be colored or left blank according to numbers at the side of the ...
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### A fun and simple Nonogram... ...with a cipher

Goal of this puzzle: Find the hidden message in this Nonogram that I created. The puzzle: play online Hint:
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### Knights and knaves variations

The knights and knaves puzzle is old, well known and thoroughly solved. https://en.m.wikipedia.org/wiki/Knights_and_Knaves In Labyrinth there's a variation, where one of the participants tell us the ...
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### Touching Base (Checkered Fillomino)

This is a Checkered Fillomino puzzle, with the following rules (adapted from the linked page): All numbers on the grid must be part of a polyomino of the same value. No two polyominoes of the same ...
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### A (maybe) simple Hokuro puzzle

Hokuro is a puzzle that was introduced to the Puzzling Stack Exchange on December 2nd, 2020 by sarsapilla as an entry for Fortnightly Topic Challenge #44: Introduce a new grid deduction genre to the ...
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### Sudoku variants #1: Schrödinger's Grave (6x6 grid)

Not in conjunction with my Minesweeper puzzles - that would be concerning! Inspired by Cracking The Cryptic's video "The Graveyard Of Schrödinger" (original gimmick by fjam) How this ...
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### A Trivial Pursuit #25: Meta-Analysis

This is the final part of A Trivial Pursuit, a 25-part puzzle hunt. Having solved the previous 24 sub-puzzles in this series, you have managed to find 24 keywords that will help you extract the ...
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### How do I determine whether a 5x5 Lights-Out puzzle is solvable without trying to solve it?

The following two 5x5 Lights-Out puzzles are not solvable. Is there a way to find out why, without trying to solve them? [1, 0, 0, 1, 0] [1, 1, 1, 1, 0] [1, 1, 1, 0, 0] [0, 0, 1, 0, 0] [1, ...
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### A 10x9 Hidato puzzle with a cipher

rot18(A se zgfwkldq jwsddq tsv sl ujwslafy hmrrdwk kg zghwxmddq sl kgew hgafl A sulmsddq kzgo aehjgnwewfl dgd) You might note that something is off about the following Hidato puzzle. Well, I guess in ...
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### Filling in an 8x8 minesweeper grid with mines (Day 9: Complex mines)

Contains: Complex mines ($i$ mines, where $i:=\sqrt{-1}$), Anti mines (-1 mines) Note: This is in conjunction with my Minesweeper puzzles Sorry for not posting a Minesweeper puzzle yesterday. I will ...
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### A 4x4 sudoku shouldn't be that hard, right? Right?

Note: this is not in conjunction with my Minesweeper puzzles Got this idea from one of Cracking the Cryptic's videos, I don't remember which one though. This exact puzzle is still overall unique. ...
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### An introduction to Hidato (also known as Hidoku)

Note: this is not in conjunction with my Minesweeper puzzles In all honesty, I don't know why I decided to look up this type of puzzle since I also have never heard about it, and there doesn't appear ...
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### Filling in an 8x8 minesweeper grid with mines (Day 8: Not a single mine)

Difficulty (approximate): ★★★☆☆ Contains: Double mine, triple mine Now you might be wondering: If this puzzle contains not a single mine, then why does it contain mines? Well, that's because there ...
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### Filling in an 8x8 minesweeper grid with mines (Day 7: Double Mines)

Note: This uses anti, single, double, and triple mines Yes, I realize that when I uploaded Day 6, I mentioned in the disclaimer that I planned for this to be released tomorrow, along with Day 8, ...
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### Filling in an 8x8 minesweeper grid with mines (Day 6: Anti-Mines - A better introduction)

Disclaimer: ascii85(Z85 (ZeroMQ) encoding)(...
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### Construction of non-rhombus but still paralellogram non-square-non-rectangle non-kite via Pythagorean triplet

Is it possible to construct a non-rhombus but parallelogram and quadrilateral non-square, Non-rectangle by putting four 3-4-5 (Pythagorean triplet) triangles together and making the 90 degree angle ...
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### The thief, liars, and the honest

There are four people: A, B, C, D. One person is a thief, the thief and two other people are lying. The other person is telling the truth. Who is telling the truth? A: I am not the thief. B: D is ...
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### Filling in an 8x8 minesweeper grid with mines (Day 5: Mod 4)

Disclaimer: ascii85(z85 (Zero MQ) encoding)(...
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### Filling in an 8x8 minesweeper grid with mines (Day 4: Looking Up)

We have a sort of weird condition for the tiles today. What is that, you ask? Well, we actually have 2: The visible neighbors are different. Here is what they will be for today (the "x" ...
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### Filling in an 8x8 minesweeper grid with mines (Day 3: Zen Garden Intro)

This day is inspired by Day 20 of the Minesweeper Advent Calendar on heptavegeesimal.com rot13(ab jnl! vzntrf jbex ba gnoyrf! :Q) okay hopefully this is my easiest Minesweeper puzzle so far Today we ...
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### One always tells truth and the other lies, figure which is which in only n tries

Here's a simpler and finalized version of the puzzle, the previous got messy due to its WIP status. Enter the hall of the twin oracles. One of the oracles is true, and its purpose is to always tell ...
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