# Questions tagged [logic-grid]

Logic grid puzzles, first produced by Lewis Carroll, are puzzles in which correspondences must be drawn between multiple ways of describing the same list of objects, using a given set of clues about these correspondences. Such puzzles can be solved using a grid, but for pre-existing grids whose elements must be filled using logic, use the [grid-deduction] tag instead.

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### Five coins on a 15x15 board

[Note: this puzzle is derived from a coding contest question at HackerRank. The question is no longer in active use there. It was originally posted with content copied-and-pasted directly from there, ...
396 views

### Raven's matrices

Is anyone able to solve this matrix? It came up on a practice aptitude test I'm taking and this one in particular had me stumped. Thanks!
3k views

### Meeting Room - a harder variation of the classic Zebra Puzzle

You can play it online here: https://www.brainzilla.com/logic/zebra/meeting-room/ ...
361 views

Persons: ...
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### Adventure of LALO : Open the Stargate Portal

While exploring a remote island under the project "Search for Knowledge Program", Archaeologist "LALO" has found a hidden stargate which will open a portal to the Knowledge Dimension. In order to ...
738 views

### Logic problem about five thieves

The teacher of my nephew (15y) proposed the following puzzle to the students. I solved it, but I found it extremely difficult, in particular for teenagers. Perhaps there is a simpler solution than ...
1k views

### A Day at the Zoo

You find a note on your door when returning home. It tells you to check your email and find the hidden message. Upon inspection, there is a mysterious email in your inbox. From: ...
1k views

### How do I solve this logic puzzle?

I am trying to improve my logical thinking and I came across this puzzle problem. I need some help solving the puzzle below. Two weeks ago, four enthusiasts made sightings of objects in the sky in ...
394 views

### The mysterious theft in the Nigerian ship

The Nigerian captain Abomeli Iweala was carrying his ship across the Atlantic Ocean, taking with him five foreigners who worked for him. One day the alarm bell rang, and when the captain arrived he ...
1k views

### Trick or Treating in Trutham-And-Ly

An entry in the 19th fortnightly challenge... Trutham-And-Ly, you may remember, is a small town in the north of Logistan. It is divided into two districts, Trutham and Ly, separated by a small stream....
2k views

### Can you solve the 7x7 (sudoku-ish) centered sums puzzle

I have come across this puzzle a few times in competitions and rally's, and it has troubled me because I cannot seem to find a good approach to solving it, either programmatically or numerically. And ...
1k views

### My version of the Einstein Riddle

Below is a puzzle that I have created, with great inspiration from the Einstein Riddle. There are 5 houses, each house has one unique owner (for the sake of clarity, let's assume that the owners are ...
1k views

### 5x5 statement table

Statement table. 3 2 1 4 1 2 3 3 3 3 3 4 6 4 4 2 3 4 4 3 1 1 2 4 3 Above 5x5 table contains numbers. A number at each cell represent a statement. x : This ...
1k views

### Athletes at the Rio Olympics

This is an entry in the 13th Fortnightly Topic Challenge. The little country of Asrius finally made it into the Olympics game! Yay! CROWD CHEERING!!! Five competitors from this country (Martin Fuis,...
452 views

### Megan and the rambling reshuffle

When I met Megan the other day in Starpounds, she was not her usual calm self. "Goodness, what a shake-up! Everyone shifted from one job to another..." "The Cabinet reshuffle?" "Blithering ramblers!...
199 views

### A group of friends at a restaurant.

Four groups of four friends each are having dinner at a restaurant. There are four tables, table A, B, C, and D, seating four each, arranged in a square like so. A B C D Each table looks like this. ...
521 views

### 'Companion Planting' Logic Puzzle - Is there an elegant solution?

Problem: You're a vegetable gardener planning to plant out seedlings in a new garden bed, however your farmer's almanac has outlined a system of rules about what plants can and cannot be placed next ...
391 views

### What is the smallest rectangle containing the squares of 1 through 100?

Let us suppose that we have an $m\times n$ grid such that every element is a digit in base $10$. Then we can read the numbers from a grid such that we fix a starting element and go to one of the eight ...
565 views

### Who likes Actress E?

This is a logical puzzle that I found, but I can't for the life of me figure out who likes Actress E and hence I'm stuck. The question is as follows : At a movie theatre six people are randomly ...
645 views

### Five Cousins Camping

Five cousins are camping together. Two are from Montana, and three are from Wyoming. Two are Pattersons, and three are Andersons. Irene and Yvonne are from the same state, while Michael and Emily ...
2k views

### 8 men in a restaurant

I know this puzzle is easy, but I hope it isn't too easy... If it is I really have to work on my puzzle-creation skills :P Story & Question: 8 men plan to go eating to a restaurant, where they ...
594 views

### Circular arrangement Puzzle

I was given this puzzle: Eight friends (Romil, Ramesh, Rakesh, Rohit, Rahul, Abhijeet, Abhishek and Anil) are sitting around a circular table, but not necessarily in the same order. Four of them ...
771 views

### How to check a partial Einstein's-like-puzzle solution

John has started an Einstein's-like puzzle ("$n$ people of $n$ ages prefer $n$ foods, etc.; determine which is which from the following facts"), using a matrix for his work. He shows me his completed ...
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### Which lorry is carrying drugs?

Five lorries are parked in a French layby, having recently come off the ferry at Calais. The police know that the lorry headed for Lisbon is smuggling drugs, but they're not sure which one it is. All ...
1k views

### Einstein's puzzle [duplicate]

There are 5 houses in 5 different colours. In each house lives a person of a different nationality. The 5 owners drink a certain type of beverage, smoke a certain brand of cigar, and keep a certain ...
2k views

### Eight animals are sitting around a circular table

Eight animals named E, F, G, H, J, K, L and M are sitting around a circular table facing the centre. These are the kinds of the animals: Cat, Cobra, Dog, Elephant, Falcon, Llama, Panda and Sparrow (in ...
227 views

### Sudoko-net pseudo-solvable with minimum blocks

A sudoku net is defined here. A sudoku net is defined as 'pseudo-solvable' if we can deduce at least two valid 'not unique' solutions . friendly sudoko is defined here What is the sudoku ...
529 views

### Enlightened, Part II: A Curious Courtyard

If you care about the story, you may want to see Part I if you haven't already. Otherwise, just enjoy the puzzle! Ricky: Chris! Chris: What is it this time? Ricky: We have another problem. Chris: ...
747 views

### Unsolvable sudoku net with maximum blocks

Definitions For a $9\times9$ grid $G$ (not necessarily respecting sudoku rules), a subset of cells $S$ is defined to be sudoku-friendly if the values in $S$ do not contradict the rules of sudoku. ...
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### The Pirates of Beal Isle - very long logic grid puzzle

Story Let me tell ye a tale: Somewhere northeast o' the Bahamas there be a tiny scrap o' rocks stickin' up out o' the sea known as Beal Island. It be a barren, rocky place, and no man ever called it ...
415 views

### The Roman Crypto

This was found engraved into a stone in Roman times: And underneath, an inscription: eoofrddene·en.do·xfrtfscqqiiut·iucraeiuioceaarriocsrt·s·ieaei,imt·oesa·serism?·,· Even with only this minimal ...
242 views

### Puzzling comes from within

People often say that the power to do things comes from within. In this puzzle, maybe I have taken that a bit too literally... I'm sure you will be able to find the sentence hidden inside this image. ...
588 views

### When will the matrix turn to black?

For the following pattern of filling the $5*5$ matrix, how many steps does it take to turn all cells of the matrix to black? Pattern has revealed by eBusiness: I guess after some steps next pointed ...
251 views

### Non-Diagonal Pointing Problem

You can see the rules for pointing problem at this article. It has been clarified that there is no solution to this question. But, what if we remove the diagonal rule? is there any solution?
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### Write digits 1 to 9 in the table, each pointing to next 3x3 grid

Write 1 to 9 digits in an empty Sudoku table with these rules (similar to 9-Queen problem): There are 9 Boxes indexed from 1 to 9 in the image below. and each box has a 3x3 grid child. Every two ...
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### Integer grid problem

I found this programming related problem too difficult for me. The problem asks to find 16 integers and form a 4x4 grid \left(\begin{array}{cccc} n_1 & n_2 & n_3 & n_4 \\ n_5 & n_6 &...
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### Put numbers from 1 to 6 in the puzzle

Put the numbers from 1 to 6 in the puzzle in a way such that: In each row or column there shouldn't are no duplicate numbers. The squares that are joined together have the same number.
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### When and where was the first logic-grid-based puzzle published?

Logic puzzles with a set of conditions and a "logic grid" are very popular. More than one publisher is currently producing puzzle books with these types of puzzles. A Wikipedia article claims ...