ISL 2020 N7
Let be a set consisting of positive integers, none of which is a sum of two other distinct members of . Prove that the elements of may be ordered as so that does not divide for all . (Ukraine)
Dataset text NuminaMath olympiads. Quoted with source.
Official text: IMO 2020 Shortlist booklet, page 12.
Solutions
Official solution Solution 1 by the IMO Problem Selection Committee
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