0 votes 0 votes Show that in a group of $10$ people (where any two people are either friends or enemies), there are either three mutual friends or four mutual enemies, and there are either three mutual enemies or four mutual friends. Combinatory kenneth-rosen discrete-mathematics counting pigeonhole-principle descriptive + – admin asked Apr 29, 2020 admin 328 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.