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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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 ...
- 75.4k
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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
...
- 6,954
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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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5
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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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You need to unfold the given figure
Unfold the given shape and find the answer
Source: UCEED (entrance exam for design colleges in India)
The given answer is B. I don't understand why this is the answer; how can I approach this kind of ...
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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 ...
- 75.4k
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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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3
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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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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 ...
- 75.4k
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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 ...
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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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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 ...
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If A cents can be paid with B coins then prove that B dollars can be paid with A coins
Looking for an intuitive solution to the following problem:
In a certain country the following coins are in circulation: 1 cent, 2 cents, 5 cents, 10 cents, 20 cents, 50 cents, and 1 dollar. It is ...
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Logic and geometry problem 2
My question is whether or not a deadlock can occur in Crisscross. A deadlock is defined as a position, an arrangement of checkers, in which the board has been filled but neither player has won.
...
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The Metaslitherlink
This puzzle is part of the Monthly Topic Challenge #13: Variety Slitherlinks.
Below is a grid containing multiple small slitherlinks. These can be independently solved to form clues for the large ...
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Sheets of paper on foreheads in a quiz show [duplicate]
I have got a puzzle that I wanted to share.
In a quiz show, three candidates were shown five slips of paper - three white and two black. Then they were blindfolded and one of the slips of paper was ...
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Lightbulbs in Two Separate Rooms
You are in a room with six light switches. Down the hallway, there are two other rooms, each with three incandescent lightbulbs.
Each lightbulb is uniquely controlled by exactly one of the switches. ...
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Logic puzzles: Flags and Stripes
Puzzle 1
Puzzle 2
Clues
The only instructions given to solve this is that the answer can be alpha-numeric text.
Ideas
Puzzle 1:
3 flagpoles seem to have top-balls (called a truck), while 3 don't
...
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Shape puzzle, find the final sequesnce or word? [closed]
Clues:
The only instructions given to solve this is that the answer can be alpha-numeric text.
Ideas:
So far I have this:
SQUARE: 101111
DIAMOND: 2111112
RECTANGLE: 111211021
HEXAGON: ?1?1011
Though ...
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Puzzle Challenge: Unraveling the the Circular Conundrum
Known are five numbers: 1, 2, 3, 4, and 5, arranged clockwise. The number after 1 is 2, after 2 is 3, after 3 is 4, after 4 is 5, and after 5 is 1. Whenever two adjacent numbers meet, it triggers a ...
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Logic and geometry problem
My question is whether or not cycles can occur in the abstract game, Clearcut.
Clearcut
A few smart guys (and me) have been trying to either find a cycle or prove that one can't happen. Ten days ...
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votes
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Is the Parity Sudoku solvable?
I have a new kind of grid puzzle (you could call it a variant of sudoku) I will be calling a Parity Sudoku.
Parity Sudoku is played on a 6x6 grid of integer cells with numbers ranging from 1 to 6. It ...
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How is the tree colored?
Not relevant fiction context
Paul's journey in the mathematical forest began this early morning. You know, he is a Biomathologist!
He saw a lot of spectacular plants, geometrical flowers and fractal
...
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If ABCDE*4 = EDCBA. A,B,C,D and E are all natural numbers ( 1-9) without repeating any natural number. Why is it deducible that E cannot be three?
If ABCDE*4 = EDCBA. ABCDE,EDCBA are five digit numbers. A,B,C,D and E are all natural numbers ( 1-9) without repeating any natural number. Why is it deducible that E cannot be three?
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Where to start with a large crack the lock puzzle like this?
Below is a puzzle called crack the lock. The rules are simple:
the lock contains 16 characters in this particular puzzle
No character can be used twice
the two numbers on the the far right tell you ...
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Can the solution a) of the accepted answer to the "Camels crossing a bridge" problem be extended to arbitrarily many camels?
This problem (and solution) with 5 camels each was posted here on Puzzling several years ago:
Two merchants have 5 camels each. One fine day, one of the merchants sells all of his goods in the market ...
- 11
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3
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Finding a 3-digit passcode from 4 mastermind clues
What is the logic used to solve this problem?
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Logic in the Polycule
Heavily based on a puzzle from Brainteasers and Mindbenders.
Eve's anniversary with her polycule is tomorrow, and she's bought presents for all of her partners. However, she stashed the presents in ...
- 3,730