3

Part of 1991 China National Olympiad

Problems(1)

China Mathematical Olympiad 1991 problem3

Source: China Mathematical Olympiad 1991 problem3

10

birds on the ground. For any

5

of them, there are at least

4

birds on a circle. Determine the least possible number of birds on the circle with the most birds.

combinatorics unsolvedcombinatorics