10 friends attend an amusement park, eavh visited 3 different attractions
Source: 2nd Mathematics Regional Olympiad of Mexico Northwest 2019 P2
September 7, 2022
combinatorics
Problem Statement
A group of friends attend an amusement park. Each has visited three different attractions . Leaving the park and talking to each other, they found that any pair of friends visited at least one attraction in common. Determine what could be the minimum number of friends who could walk in the most visited attraction.