17 coins, 2 arer counterfeit - All-Russian MO 2003 Regional (R4) 10.8
Source:
September 17, 2024
combinatoricsweighings
Problem Statement
In a set of 17 externally identical coins, two are counterfeit, differing from the rest in weight. It is known that the total weight of two counterfeit coins is twice the weight of a real one.s it always possible to determine the couple of counterfeit coins, having made weighings on a cup scale without weights? (It is not necessary to determine which of the fakes is heavier.)