MathDB
Math Prize 2019 Problem 18

Source:

October 15, 2019
Math Prize for Girls

Problem Statement

How many ordered triples (a,b,c)(a, b, c) of integers with 15a,b,c15-15 \le a, b, c \le 15 are there such that the three equations ax+by=cax + by = c, bx+cy=abx + cy = a, and cx+ay=bcx + ay = b correspond to lines that are distinct and concurrent?