Olympiad Maths Prep

Track / Stage 4 / 84 of 340 #344 of 2000

Problem 344

AMC 12 late, AIME early
Combinatorics Difficulty 4.8 Find the answer

3. 4. In a computer game, a turtle moves across a grid on the computer screen, which contains 5 columns and 9 rows. Initially, it is located in the bottom-left corner of the screen - on the cell with coordinates (0,0)(0,0). If the program instructs the turtle to move off the screen, it reappears on the opposite side - for example, taking one step up from the cell (3,8)(3,8), the turtle will end up in the cell (3,0)(3,0). Where will the turtle end up after executing the following program:
1) 1 step up; 2) 2 steps to the right; 3) 3 steps down; 4) 4 steps to the left; 5) 5 steps up; 6) 6 steps to the right; ...; 2016) 2016 steps to the left; 2017) 2017 steps up

Official solution

Answer: (2;1)(2,1)2;12,1(2 ; 1)\|(2,1)\| 2 ; 1 \| 2,1

Examples of answer notation:

(1;7)(1 ; 7)

#

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.