Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2015-part-03 — 191 problems (EN–VI) Question 59

Math Olympiad Vault · MathNet 2015-part-03 — 191 problems (EN–VI)

Question 59

Find the maximum number of sets which simultaneously satisfy the following 3 conditions:
(i) any of the sets consists of 4 elements;
(ii) any two different sets have exactly 2 common elements;
(iii) no two elements are common to all the sets.