MathDB

9.5

Part of 2003 All-Russian Olympiad Regional Round

Problems(1)

100 people came to party - All-Russian MO 2003 Regional (R4) 9.5

Source:

9/17/2024
100100 people came to the party. Then those who had no acquaintances among those who came left. Among those who remained, then those who had exactly 11 friend , also left. Then those who had exactly 22, 33, 44,.. . . , 9999 acquaintances among those remaining at the time of their departure did the same..What is the largest number of people left at the end?
combinatorics