2
votes
3answers
43 views

Permutation and Combination Puzzle - Spy Keypad

Keypad 1 2 3 4 5 6 7 8 9 J. Bond has to break into the headquarters of an evil organization and steal important documents. The documents are in a safe that can ...
2
votes
2answers
101 views

Is there a solution to this Seating Plan problem?

So a colleague asked me for some Help on an interesting Problem, which we both couldn't find the optimal answer for. The event which needed it is already in the past, so this is just me trying to ...
0
votes
2answers
302 views

How do I find the maximum number of knights on a chess board?

I came across this problem and after thinking a lot I could not get any idea how to calculate it. Please suggest to me the right way to calculate it. Given a position where a knight is placed on ...
1
vote
1answer
187 views

How many unique patterns exist for a 5x5 grid with paths of spaces intersecting at 1 space and leading to each edge of the grid?

I'm try to design a game in which the board is made up of a 3x3 grid of square tiles. Each tile is a 5x5 grid of spaces. Each tile has 4 exit spaces each located on 1 of the middle 3 spaces along ...
1
vote
0answers
450 views

what is maximum number of points of intersection between the diagonals of a convex octgon?

What is the maximum number of points of intersection between the diagonals of a convex octagon (8-vertex planar polygon)? Note that a polygon is said to be convex if the line segment joining any two ...
1
vote
1answer
228 views

Puzzle of $N$ men around a table

This was asked to me by a friend. $N$ men sit around a circular table. Man 1 has a sword with him and he kills the Man 2, Man 3 picks up this sword and kills the next person i.e. Man 4. Thus the man ...
27
votes
1answer
1k views

Six Frogs - Puzzle

I had come across a puzzle: The six educated frogs in the illustration are trained to reverse their order, so that their numbers shall read 6, 5, 4, 3, 2, 1, with the blank square in its ...
2
votes
2answers
643 views

Puzzle, Permutation and Combination problem?

I have a puzzle here: There are five colored balls: 2 green, 2 blue and 1 yellow Rule 1: All balls of the same color must be adjacent to each other. I wrote a program to find all the ...
3
votes
1answer
243 views

There is a 5 by 5 matrix of points on a plane. How many triangles can be formed using points on this matrix?

There is a 5 by 5 matrix of points on a plane. How many triangles can be formed using points on this matrix?
2
votes
1answer
206 views

When does an orthomorphism of the cyclic group exist?

I thought I would post (as a puzzle) one of my favourite results in combinatorics. I actually use variants of this result in research quite often. It's not impossible that someone will post an ...