2

Part of 2019 Regional Olympiad of Mexico Northwest

Problems(1)

10 friends attend an amusement park, eavh visited 3 different attractions

Source: 2nd Mathematics Regional Olympiad of Mexico Northwest 2019 P2

10

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.