Tourism In Five Villages
Source: 2008 Greek TST,Pr.2
May 25, 2016
combinatorics
Problem Statement
In a village there are tourists who are about to visit nearby villages .Each of them has chosen to visit only one of them.However,there are cases when the visit in a village forces the visitor to visit other villages among .Each tourist visits only the village he has chosen and the villages he is forced to.If are totally visited by tourists respectively,then find how many tourists had chosen each one of them and determine all the ordered pairs which are such that,the visit in forces the visitor to visit as well.