numbers in a 2015 x 2015 table
Source: 2016 Saudi Arabia Pre-TST Level 4+ 1.4
September 13, 2020
combinatoricstable
Problem Statement
The natural numbers are written on the square table 2015\times 2015 in a circular order (anti-clockwise) such that is in the center of the table. The rows and columns are labelled from bottom to top and from left to right respectively. (see figure below)
1. The number is in which row and which column?
2. We are allowed to perform the following operations: First, we replace the number in the center by , after that, each time, we can add to each of numbers on consecutive unit squares in a row, or consecutive unit squares in a column, or unit squares in a rectangle . After a finite number of steps, can we make all numbers on the table are multiples of ?
https://cdn.artofproblemsolving.com/attachments/c/d/223b32c0e3f58f62d0d40fa78c09a2cd035ed5.png