10 pople in a a bookstore for science.
Source: Portugal OPM 2002 p6
May 19, 2024
combinatorics
Problem Statement
On March , , the celebrations of the th anniversary of the birth of by mathematician Pedro Nunes. That morning, only ten people entered the Viva bookstore for science. Each of these people bought exactly different books. Furthermore, any two people bought at least one copy of the same book. The Adventures of Mathematics by Pedro Nunes was one of the books that achieved the highest number of sales in this morning. What is the smallest value this number could have taken?