Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2022-part-04 — 197 problems (EN–VI) Question 99

Math Olympiad Vault · MathNet 2022-part-04 — 197 problems (EN–VI)

Question 99

At a gala banquet, $12n + 6$ chairs, where $n \in \mathbb{N}$, are equally arranged around a large round table. A seating will be called a proper seating of rank $n$ if a gathering of $6n + 3$ married couples sit around this table such that each seated person also has exactly one sibling (brother/sister) of the opposite gender present (siblings cannot be married to each other) and each man is seated closer to his wife than his sister. Among all proper seats of rank $n$ find the maximum possible number of women seated closer to their brother than their husband. (The maximum is taken not only across all possible seating arrangements for a given gathering, but also across all possible gatherings.)