There are given points with integer coordinate $(m,n)$ such that $1\leq m,n\leq 4$. Two players, Ana and Ben, are playing a game: First Ana color one of the coordinates with red one, then she pass the turn to Ben who color one of the remaining coordinates with yellow one, then this process they repeate again one after other. The game win the first player who can create a rectangle with same color of vertices and the length of sides are positive integer numbers, otherwise the game is a tie. Does there exist a strategy for any of the player to win the game?
Problem
Source: Kosovo MO 2019 Grade 11, Problem 5
Tags: analytic geometry, geometry, rectangle
10.03.2019 15:33
Who is going to try this?
10.03.2019 16:15
dangerousliri wrote: There are given points with integer coordinate $(m,n)$ such that $1\leq m,n\leq 4$. Two players, Ana and Ben, are playing a game: First Ana color one of the coordinates with red one, then she pass the turn to Ben who color one of the remaining coordinates with yellow one, then this process they repeate again one after other. The game win the first player who can create a rectangle with same color of vertices and the length of sides are positive integer numbers, otherwise the game is a tie. Does there exist a strategy for any of the player to win the game? So what does it mean to "color one of the coordinates"? (1) To color all points that have this coordinate as first coordinate? (2) To color all points that have this coordinate as second coordinate? (3) To color all points that have this coordinate as first or second coordinate? (4) You may choose first or second coordinate and then color all points with the chosen coordinate? (5) To color all uncolored points that have this coordinate as first coordinate? (6) To color all uncolored points that have this coordinate as second coordinate? (7) To color all uncolored points that have this coordinate as first or second coordinate? (8) You may choose first or second coordinate and then color all uncolored points with the chosen coordinate? (9) Or something else?
10.03.2019 18:55
test20 wrote: dangerousliri wrote: There are given points with integer coordinate $(m,n)$ such that $1\leq m,n\leq 4$. Two players, Ana and Ben, are playing a game: First Ana color one of the coordinates with red one, then she pass the turn to Ben who color one of the remaining coordinates with yellow one, then this process they repeate again one after other. The game win the first player who can create a rectangle with same color of vertices and the length of sides are positive integer numbers, otherwise the game is a tie. Does there exist a strategy for any of the player to win the game? So what does it mean to "color one of the coordinates"? (1) To color all points that have this coordinate as first coordinate? (2) To color all points that have this coordinate as second coordinate? (3) To color all points that have this coordinate as first or second coordinate? (4) You may choose first or second coordinate and then color all points with the chosen coordinate? (5) To color all uncolored points that have this coordinate as first coordinate? (6) To color all uncolored points that have this coordinate as second coordinate? (7) To color all uncolored points that have this coordinate as first or second coordinate? (8) You may choose first or second coordinate and then color all uncolored points with the chosen coordinate? (9) Or something else? To color a lattice point in the 4x4 grid.