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Swedish Mathematical Competition
1985 Swedish Mathematical Competition
6
6
Part of
1985 Swedish Mathematical Competition
Problems
(1)
no of citizens wanted in X-wich, people and clubs related
Source: 1985 Swedish Mathematical Competition p6
3/28/2021
X-wich has a vibrant club-life. For every pair of inhabitants there is exactly one club to which they both belong. For every pair of clubs there is exactly one person who is a member of both. No club has fewer than
3
3
3
members, and at least one club has
17
17
17
members. How many people live in X-wich?
combinatorics