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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Filling in an 8x8 minesweeper grid with mines (Day 2: Diagonal Reverse Synesthesia)
Note: This is based off of Day 30 of the Minesweeper Advent Calendar on heptaveegesimal.com
So my first minesweeper puzzle did not go so well. I will try to do better today.
First off: This is a torus ...
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Filling in an 8x8 minesweeper grid with mines (pt. 1: Rectangle)
Can you detect where the mines are in this 8x8 Minesweeper grid containing single, double, triple, and anti-mines?
1
3
4
-1
21
5
3
1
9
3
-1
3
-5
-4
-3
13
4
5
20
12
5
5
Notes:
Anti-...
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A compact grid of squares
Given the information below, connect the red point to one of the four corners of the grid, with exactly six moves.
Each move ends on a unique point
Each move, except two consecutive moves, are unique ...
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Quadritaisho: The sports bet
My friend from America was going to watch a game and wanted to bet I couldn't guess where he was going. The answer lies in the Quadritaisho puzzle below. Can you help me find out where he's going to ...
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How did the students figure this out?
A Logician meets with five of his new students. These students have never met before and do not know each other's names. The logician goes to the board and writes all their names in random order.
SAL ...
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Help me with Slitherink puzzle (honeycomb) solution
I got stuck on this level (Honeycomb/Large/Hard/#12) and I always end up having issues with the part that I circled with red because it either wouldn't add up or there would be a space that's not ...
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Quadritaisho: An introduction
TL;DR: Nikoli's Tentai Show, but with four different types of symmetry.
Rules of Quadritaisho:
Divide the grid into rooms by drawing borders along grid lines.
Each room contains exactly one symbol (...
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5
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Temple of lost memories: raiding the circular chamber
In the center room of an ancient temple, there are $n$ identical chests. Of these, $k$ contain treasure, but the other $n-k$ contain mind erasers. You do not know $k$. If you open a chest with a mind ...
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Multi smol boi puzzle I: apologies
Disclaimer: Jryy, svefg bs nyy, V jbhyq yvxr gb ncbybtvmr. Abg sbe npgvbaf (jryy bxnl, sbe npgvbaf), ohg sbe zl fzby obv pvcure. Vg frrzf gung zl svefg fzby obv chmmyr jnf whfg n ovg gbb uneq. Fb, gb ...
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Max/Min points in Tournament
A round-robin tournament with 10 people.
Find the maximum possible points for second place
Find the minimum possible points for second place
Find the maximum possible points for second last place
...
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2
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How to remember without writing, a subset of 1000 numbers [closed]
P has a secret number which is between 1 and 1000 (both inclusive).
Q tries to guess the number by speaking out random numbers one by one.
R has to keep track of all the numbers that Q has spoken. An ...
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A Trivial Pursuit #19 (Geography 4/4): Glass
This is part 19 of A Trivial Pursuit, a 25-part puzzle hunt. Each part is solvable on its own, with the exception of the meta-puzzle at the end.
Front of menu card:
STIV'S SPEAKEASY
COCKTAILS
BOUR....
- 134k
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SlitherLITS revisited - Do colour outside the lines
This is a follow-up to SlitherLITS: Don't colour outside the lines
After creating that puzzle, I've been wondering whether it was possible to create a SlitherLITS puzzle where all the regions outside ...
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An anagrammed logic puzzle!
ot rleow utbrctsa aacpilt hwti
dioiatdn het ryuo
s-bcBPEFfJDfeFmksmPOkChDhrgBqjD-i---ffeNB
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Playing Mastermind against an angel and the devil
This puzzle is based on a card game. There are 7 suspects and 3 of them committed a crime. The game contains 35 cards that contain the 35 possible choices of 3 out of the 7 suspects. One card is drawn ...
- 1,691
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Colourful Scenery
This is part 41 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
This is a Word Nurikabe puzzle. Shade some cells in the grid. Shaded cells must ...
- 76.4k
18
votes
1
answer
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A Trivial Pursuit #12 (Sports and Leisure 2/4): Logic Boat
This is part 12 of A Trivial Pursuit, a 25-part puzzle hunt. Each part is solvable on its own, with the exception of the meta-puzzle at the end.
This is a variation on a Battleships puzzle, where the ...
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Logic and Geometry Problem #5: does Savage Go have cycles?
My question is whether or not a cycle can occur in the game of Savage Go. That is, you kill some of mine, I kill some of yours, you kill some of mine... Endless cycle of turns. Game never finishes.
No ...
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Very small regional Yajilin
This puzzle is part of the Monthly Topic Challenge #14: Think inside the (very small) box!.
Rules of regional Yajilin:
Shade some cells in the grid. Two shaded cells cannot share an edge, but can ...
- 76.4k
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votes
1
answer
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Nonogram with story
Fellow puzzlers, here's a nonogram I made for you. But it also has a story!
Two bored male casino dealers are waiting at the craps table. A very attractive blond woman arrives and bets $20,000 on a ...
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Continue the squence of hexagons
This is from c't, a German IT magazine (link will download file). You see seven hexagons, each with seven green and blue dots, following a specific rule. Find out what colors the circles must have to ...
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Justifying a redouble
This puzzle is derived from a real game of bridge I played on Bridge Base Online.
I was sitting North on board 9 (N dealer, E-W vulnerable) and the bidding turned out like this:
West
North
East
South
...
- 7,006
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A Problem in Research using Logic
Here's a problem of my own design. You are researching 5 papers done in your field in order to guide your next paper. Some papers may have had a bad study design, used faked data, or otherwise would ...
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“Pickled Walnuts” Logic Problem
Here's a problem by puzzle composer Hubert Phillips called “Pickled Walnuts”. What conclusions (if any) can be drawn about armadillos and picked walnuts, assuming all statements are true?
Pickled ...
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What was the date of Michael's birth?
Michael was so obsessed with his birthday that he always held his birthday party on the exact date and time of his birth. But he didn't hold his birthday for 8 years (he held his 16th birthday and ...
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What are the largest and smallest numbers in decimal base in this special Sudoku?
I have constructed the following hexadecimal 16×16 sudoku in this site:
The rules are like 9×9 sudoku tables (each number and letter should repeat only one time in each column, row, and 4×4 ...
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Mexican Standoff -- 4 way
You and 3 others are being held captive by the Great Leader and will be forced to engage in a 4-way shootout. The last one standing will be set free and the top priority for all involved is to go ...
- 559
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Find unique values for the variables to make all statements true
In this puzzle you have to find unique values for the variables to make all statements true. I have proceeded to here and now I seem to be stuck.
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gambas al ajillo
This is a Tapa puzzle. That means you must shade some of the squares, so that:
No square containing text is shaded.
Numbers in a square indicate runs of consecutive shaded squares among the ≤eight ...
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votes
3
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Logic and geometry problem #4: are these games functionality equivalent?
Two games, Crossway and Mincut, are believed to be functionally equivalent. That is, a win by Crossway rules will necessarily lead to a win by Mincut rules. And a win in Mincut will be a win in ...
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Find the Rat in the Hole
A rat is in one of 100 holes that are in a line. Each night he moves to the left or right 0,1, or 2 holes randomly selected. You pick one hole each day to look in until you find him. What procedure ...
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Slither-Yajilink: A match made in Hades
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
This is a Slitherlink-Yajilin hybrid. Shade some cells in the grid and draw one non-crossing, non-branching line ...
- 76.4k
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Was Humpty Dumpty right?
Raymond Smullyan's What is the Name of This Book? contains a puzzle which I'll paraphrase here:
Of the identical twins Tweedledum and Tweedledee, one of them lies on Mondays, Tuesdays and Wednesdays ...
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Zodiac Signs at the Table
"And we find ourselves at another one of Ophiuchus' little themed puzzle dinners," you say while glancing at the other seven people.
"I really like its puzzle dinners, honestly," ...
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Seven similar 7x7 (pen-and-paper) logic puzzles
Oh no! I've just finished drafting some 7x7 logic puzzles, but I accidentally dropped all of them on the floor, and now they're all mixed up!
To make matters worse, I haven't gotten around to ...
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A Watery Slitherlink
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
A watermill is going to be built next to a cozy town. You are the designer of the aforementioned mill/slitherlink, and ...
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Alice knows a+b, Bob knows a×b. Can we find (a,b)?
There are two distinct positive integers $a,b$ (i.e. $a\neq b$) such that $a < 7$ and $b < 7$.
Alice has been told the sum of $a$ and $b$. Bob has been told the product of $a$ and $b$.
Both ...
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1
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Logic and geometry problem #3: are cycles possible in Scattercut with added "maximum" rule?
My question is whether or not cycles can occur in the game of Scattercut. That is, you kill some of mine, I kill some of yours, you kill some of mine... Endless cycle of turns. Game never finishes.
...
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Beauty, chef and boxer
Sarah, Megan, and Mike all attended a party last night. Sarah is a beauty pageant winner, Megan is a chef, and Mike is a boxer. The host of the party said that one person told a lie during the evening,...
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Find the largest number with unique digits, that is divisible by each of its digits [duplicate]
Find the largest number with unique digits, that is divisible by each of its digits.
For example 132 has unique digits and is divisible by 1, 2 and 3. But it is not the largest such number. Can you ...
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Assemble n^3 cubes into n different n×n×n larger cubes [duplicate]
You might have seen this question before:
Goal: Paint 27 cubes using three colors (for example, red, yellow, and blue), so that you can form a 3x3x3 cube with all surfaces in red (for example), a ...
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Nurikabe: Forties
The good news: It’s my birthday! The bad news: I’m 40 now. It’s not a great update. Just weaker stats with no cool new abilities. Anyway, here’s a Nurikabe to celebrate. Don’t worry, it should be good ...
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Double trouble - When slitherloops collide
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
What happens when you're working on a couple of puzzles for the Monthly Topic Challenge and try to merge them?
Well, in ...
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Walking a twisted path on a donut - a Möbius Slitherlink
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
Have you ever wondered why there has to be an "inside" and an "outside" to every slitherlink loop?
...
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Slither-Numberlink: A monstrosity nature never intended
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
Rules of hexagonal Slither-Numberlink:
Some numbers in the grid are slitherlink clues, some are numberlink clues. Zeroes ...
- 76.4k
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Counting Tic-Tac-Toe draws on larger grids
Alice and Bob play a game of Tic-Tac-Toe on a grid of size $N \times M$. The rules of this game are the same as the original Tic-Tac-Toe:
Alice plays first (white); Bob plays second (black).
On each ...
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SlitherLITS: Don't colour outside the lines
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
Adding a bit of colour to enhance the loopy goodness of a traditional Slitherlink.
Draw a single, non-intersecting loop ...
- 14.2k
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How to solve large "crack the lock" questions
I already have the solution for this crack the lock puzzle but am stuck on how to get there. The smaller puzzles I've solved use a different style of deductive reasoning.
Rules:
For this specific ...
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Next Sudoku Number
Here is a sudoku puzzle coming from this magazine
I found that B5 and B6 can only contain 6 and 7. 8 cannot be in B5 because D1 would be a 8 and neither B3 not C1 could be a 8.
I thought it would help ...
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1
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An oddly coloured slitherlink
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
I find something strangely satisfying about a well designed slitherlink puzzle, even one which is oddly coloured and ...
- 14.2k