Sex-wise, the M-F numbers for the ten top-scoring six-member teams were 6-0, 6-0, 6-0, 6-0, 6-0, 6-0, 6-0, 6-0, 6-0, and 5-1 (she‘s an Israeli). When, oh when, shall we vanquish toxic masculinity?
Of the six problems they had to solve, only Problem 3 gave them much trouble. If you‘d like to tackle it yourself, here it is.
Problem 3. Let k be a positive integer and let S be a finite set of odd prime numbers. Prove that there is at most one way (up to rotation and reflection) to place the elements of S around a circle such that the product of any two neighbours is of the form x² + x + k for some positive integer x.