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).
3,606 questions
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An Ecumenical Matter
The priests of a certain order do not use the words "yes" and "no". Instead, they say "qui", "quae", and "quod".
That's right. Three words, each of ...
- 2,675
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numbers inside a plane tiling [closed]
Is it possible to place exactly one positive integer in each shape such that the following conditions hold?
Only the number $1$ is repeated.
Each dodecagon's number is the product of the numbers in ...
- 1
11
votes
7
answers
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Can a 10*10 square be paved with 1*4 rectangular stone plates?
Can a 10 * 10 square be paved with 1*4 rectangular stone plates?
I seek a very intuitive and simple answer to this puzzle.
P.S. Will post the source later. The source contains the answer but it is not ...
- 7,685
2
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1
answer
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Who was the murderer who wore slippers?
Puzzle #9 in A Most Puzzling Murder Mystery by Bianca Marais:
After midnight, five women sneak from the castle’s foyer to head out for various nefarious reasons.
Each of them
has a specific ...
- 51
-1
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125034 v2.11 / 2025-07-11 Q1-4(v=0)
I am developing a game that generates puzzles every day (https://125034.pages.dev/). It's my opinion that these puzzles are like Einstein's Riddle in 1D.
The game and I have created four "v=0&...
- 304
5
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0
answers
175
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What is the optimum strategy for a logic word puzzle?
I’ve made a small browser puzzle called Codextri where you have to identify a hidden set of three letters by guessing words. Each guess returns a score based on how many of those hidden letters your ...
- 51
0
votes
1
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How do I proceed with this Tango puzzle?
Rules to fill out the grid:
I must use 3 of each symbol in each row, and in each column.
I cannot use 3 consecutive identical symbols (horizontally or vertically).
A solid border indicates that the ...
- 1,429
15
votes
5
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prisoners riddle - a button, a light and a timer
Here is (yet another) prisoner riddle. I made it up (maybe it was asked before, but to the best of my knowledge I'm the first to ask it - correct me if I'm wrong).
There are 1000 prisoners who are ...
- 153
1
vote
1
answer
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My Most Recent Chess Tournament
This is a lightweight puzzle, hopefully entertaining but not difficult. Since my FIDE rating for classical Chess is 2343 at the time of writing, I recommend you do not post a solution to this puzzle ...
- 7,920
2
votes
4
answers
334
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Explain deduction from LinkedIn's Queen #564
LinkedIn's Queen #564 (HARD difficulty)
I am watching the commentary of today's Queen puzzle (a 1* Star Battle puzzle), given that I complete it in about 2 minutes. But one thing I don't quite ...
- 109
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votes
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Lewis Carroll with Probabilities
Here's a famous Lewis Carroll problem:
Babies are illogical
Nobody is despised who can manage a crocodile
Illogical persons are despised
The conclusion is: Babies cannot manage crocodiles.
I've ...
- 846
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4
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Find the missing digits in 1/2024
1/2024 is equal to $0.000\overline{a9407114b245059c88d375}$.
Can you find the values of a, b, c, and d without using a calculator?
Long division is trivial. Can you use other ways to find the missing ...
- 1,969
0
votes
1
answer
168
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Knights, Knaves and Spies, unclear solution provided
Puzzle
You are on an island inhabited by three types of people: those who only tell the truth (knights), those who only tell
lies (knaves), and those who sometimes tell the truth and sometimes tell ...
- 111
1
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Next logical deduction in this Nonogram?
I’ve been working on the following Nonogram and got stuck partway through. I’d like to continue logically rather than by guessing, but I’m not sure what the next forced step is. Here is my current ...
- 19
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Tips on solving sudokus linearly
The last number of months I have been reading about numerous ways on how to solve Sudokus. So far I am familiar with obvious and hidden singles, obvious, hidden and pointing pairs, obvious, hidden and ...
- 121
