Magnetic Cars
Source: KöMaL A. 816
March 23, 2022
komalcombinatorics
Problem Statement
Peter has pieces of magnetic railroad cars, which are of two types: some have the front with north and the rear with south magnetic polarity, and some have the rear with north and the rear with south magnetic polarity (on these railroad cars the front and the rear can be distinguished). Peter wants to decide whether there is the same number of both types of cars. He can try to fit together two cars in one try. What is the least number of tries needed?Proposed by Dömötör Pálvölgyi, Budapest