Maximum number elements in A U B
Source: Dutch IMO TST II Problem 2
July 17, 2014
number theory unsolvednumber theory
Problem Statement
The sets and are subsets of the positive integers. The sum of any two distinct elements of is an element of . The quotient of any two distinct elements of (where we divide the largest by the smallest of the two) is an element of . Determine the maximum number of elements in .