# 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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159 views

### Don't Fail MY Exam [duplicate]

A professor decides the following grading scheme in his class. After the final exam is graded, he keeps all the papers upside down on his table in a random order so that no student can recognise his ...
151 views

### Quick Moon-or-Sun Puzzles: 2x1-Dominoes and 1x1-Checkerboards

Moon-or-Sun (adapted from Nikoli) Draw a line to make a single loop. Lines pass through the centers of cells, horizontally, vertically, or turning. The loop never crosses itself, branches ...
296 views

### Quick Slitherlink Puzzles: KPK and 123

Slitherlink (taken from Nikoli) Connect adjacent dots with vertical or horizontal lines to make a single loop. The numbers indicate how many lines surround it, while empty cells may be ...
321 views

### Quick Tilepaint Puzzles: Corridors and Corners

Tilepaint (adapted from Nikoli) The areas enclosed by bold lines are called "Tiles" and color the tiles with the following rules. The cells of a tile must all be colored with black or left ...
971 views

### Isometric Heyacrazy - Now In 3D!

This is a Heyacrazy puzzle on an isometric grid. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. ...
219 views

### A Game of Sprouts

I have a partially played game of sprouts that I need help solving. The rules are simple (Kevin over at VSauce2 did a great job explaining it if you don't like reading, though the Yoda voice is a bit ...
167 views

### Heyacrazier: Big Three

This is a Heyacrazier puzzle, a variant of Heyacrazy. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally ...
198 views

### Lady C gives 11 different numbers one of which is her age to logicians A and B. What is the age of lady C?

Logicians A and B ask lady C her age. Lady C gives 11 different numbers one of which is her age to logicians A and B: 35, 36, 38, 42, 45, 46, 51, 55, 57, 61, 62 Then lady C tells the digit in tens to ...
6k views

### Half filled water bottle

If you are given a marker and a transparent water bottle partially filled with water, can you tell if the bottle is half filled or not?
315 views

### Toroidal Heyacrazy: Rainstorm

This is a Toroidal Heyacrazy puzzle. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the ...
310 views

### Is this robot-programming puzzle solvable?

I have gotten into solving this kind of puzzle recently. I've found this one and after an hour of trying, I don't seem to be able to find a solution. I'm starting to think there might be an error and ...
258 views

### A balloon and a vacuum

You have a metal water bottle entirely filled with a vacuum and you have a rubber party balloon (lets make it red). How can you use only the bottle to inflate the balloon with the air surrounding you. ...
178 views

### Heyacrazy: Dissection

This is a Heyacrazy puzzle. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the puzzle is ...
2k views

### Stuck on a puzzle

I have been working on a Knapp Daneben Tapa, where each clue is wrong by exactly one unit. I have tried it a few times and keep running into the same problem. I think I am solving it deductively/not ...
410 views

### Heyacrazy: Empty Space

This is a Heyacrazy puzzle. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the puzzle is ...
16k views

### Get 100 as an answer on a calculator without using 0

Task Get 100 as an answer with only four keystrokes on a regular calculator. Disallowed keys 0 00 Allowed keys All other than the aforementioned two keys. Take the below image as a reference. ...
246 views

### Heyacrazy: No Diagonals

This is a Heyacrazy puzzle. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the puzzle is ...
225 views

### Heyacrazy: Careening

This is a Heyacrazy puzzle, designed at request of testsolvers of previous puzzles who wanted to see how longer diagonals would work. Rules of Heyacrazy: Shade some cells of the grid. Shaded ...
604 views

This puzzle is a combination between a Slitherlink and a Fillomino. You should put a number in each square and draw a single closed loop over the grid such that the following properties are satisfied:...
972 views

### Earth rotation discrepancy

Some time ago, I discovered that planet earth's sidereal rotation period equals 23 hours, 56 minutes, and 4.1 seconds (see for example this Wikipedia article). The sidereal rotation is the rotation of ...
192 views

### Heyacrazy: “LMI”

This is a Heyacrazy puzzle, originally constructed for a test for Logic Masters India. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded ...
180 views

### Heyacrazy: Forks

This is a Heyacrazy puzzle. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the puzzle is ...
700 views

### Heyacrazy: Crosses

This is a Heyacrazy puzzle. Heyacrazy is an original genre, inspired by the "two border" rule of Heyawake and Heyawacky. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot ...
552 views

### Masyu puzzles with many circles

The rules of Masyu: Make a single loop with lines passing through the centers of cells, horizontally or vertically. The loop never crosses itself, branches off, or goes through the same cell ...
482 views

### Heyawacky: Ace of Cups

This is a Heyawacky puzzle. The rules are the same as Heyawake, but non-rectangular regions are allowed. Rules of Heyawake: Shade some cells of the grid. Shaded cells cannot be orthogonally ...
1k views

### Heyawake: An Introductory Puzzle

This is a Heyawake ("divided rooms") puzzle. Rules of Heyawake: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. ...
332 views

### Black to play and win (Teeko)

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260 views

1k views

### Single Colour Mastermind Problem

Imagine we're playing a game of mastermind with the usual eight colours, only this version has six holes across in which to place colours. And to make it easier for you I tell you that I have filled ...
709 views

### Bongard n°4: Neutral vs Town

This is my last puzzle before the holidays, have a nice summer everyone. Here's a link to the rules of these kind of problems: There are six boxes on the left, and another six on the right. The ...
165 views

### A riddle from Candy Cadet [closed]

I am Candy Cadet, come get your candy here. I have candy all day, everyday. Candy. Candy. Candy. Now I will tell you a story about a young woman who was sealed in a small room. In the room was a ...
512 views

### Can you solve this masyu puzzle?

Hey guys, enjoy this masyu puzzle! For those unfamiliar with masyu, here are some instructions: The goal of Masyu is to connect the circles on the grid via a line that closes itself and also does ...
934 views

### A Total Masyu puzzle

In a Total Masyu puzzle, one must draw a single loop through the centres of some cells according to the following rules: The loop may only travel horizontally or vertically, never diagonally; all ...
3k views

### Help me, I hate squares!

There is $5$x$5$ equidistance matrix dot given as below; You need to remove dots from the figure where it will be impossible to form a square by drawing lines between dots at the end. So what is ...
85 views

### Seed is to sprout as [closed]

I came across this question and couldn’t find an answer to it. The question goes like so: Seed is to sprout as A. Plant is to grow B. Garden is to weed C. Dawn is to morning D. Teenager is to ...
406 views

### Statue Park: Apollo 11

This is a Statue Park puzzle, made in honor of the 50th anniversary of the Apollo 11 mission. Rules of Statue Park: Shade some cells of the grid to form the given set of pieces. Pieces may be ...
3k views

### The grades of the students in a class

You are a new Math 102 professor in a university class of 88 students and would like to learn their grades from previous semester to know your students better and put a note of it to get an idea how ...
888 views

### Violations of the law

I live in A but work at B. The two are 45 minutes apart and I could commute back and forth either by driving or by taking the bus. Every day, before going from A to B in the morning and before going ...
192 views

### Yajisan-Kazusan: Diagonal Arrows

This is a Yajisan-Kazusan puzzle. Rules of Yajisan-Kazusan: Several numbered arrows are given in the grid. Shade some cells so that: no two shaded cells are adjacent unshaded cells form ...
272 views

### Top Game Developers

Top Game Developers Back Story Okay fellow puzzlers, I hope you packed your lunch, this one is my most challenging puzzle to date... Johnny is writing an article about some of the top-selling ...
6k views

### Two spies throwing stones into a river

There is a puzzle about two spies: Two spies must pass each other two secret numbers (one number per spy), unnoticed by their enemies. They have agreed on a method for doing this using only 26 ...
702 views

### Legal advise for a family dilemma

"A client of mine," said a lawyer, "was on the point of death when his wife was about to present him with a child. I drew up his will, in which he settled two-thirds of his estate upon his son (if it ...
237 views

### Minesweeper challenge #4

While solving another Minesweeper puzzle, I ran into yet another unsolvable corner. Well, actually, this time I have two unsolvable corners in the same puzzle. Here's the bottom left corner: ...as ...
217 views

### Minesweeper challenge #5

Coming back to another Minesweeper challenge... I've run into another "unsolvable corner" (corner of a puzzle where there isn't enough information to be 100% certain that any particular square that ...
260 views

### The CompuTaria Quest - A young Wizard's journey

Once Upon A Time In A Land FAR, FAR Away... Our adventure begins in the enchanted land called "CompuTaria". You are, "Binaryian" a 3rd year Wizard In Training. Today began like any other day - you ...
2k views

### Missing Piece of Pie - Can you find it?

A piece is missing! What should it be?
6k views

### Escape the dungeon, by deciphering the codes and navigating the rooms to find a way out

You have been thrown into a dungeon with many rooms; you don't know who did this or why. You start in room 37. You might be thinking "Why 37?", so I will explain this: "Why not?" You need to find ...
373 views

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