MathDB
E_i \cap E_j \ne\varnothing, 4mountain trips for n Alpine Club's members

Source: Austrian - Polish 1995 APMC

May 3, 2020
combinatorics

Problem Statement

The Alpine Club organizes four mountain trips for its nn members. Let E1,E2,E3,E4E_1, E_2, E_3, E_4 be the teams participating in these trips. In how many ways can these teams be formed so as to satisfy E1∩E2≠∅E_1 \cap E_2 \ne\varnothing, E2∩E3≠∅E_2 \cap E_3 \ne\varnothing , E3∩E4≠∅E_3 \cap E_4 \ne\varnothing ?
Back to ProblemsView on AoPS