JBMO-SL 2019 C1
Let be a set of 100 positive integers having the following property:
"Among every four numbers of , there is a number which divides each of the other three or there is a number which is equal to the sum of the other three."
Prove that the set contains a number which divides each of the other 99 numbers of .
Dataset text NuminaMath olympiads. Quoted with source.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.