n kinds of fruit, friends in a class
Source: 2022 Israel TST 3 P3
May 22, 2022
combinatoricscombinatorics unsolved
Problem Statement
A class has 30 students. To celebrate 'Tu BiShvat' each student chose some dried fruits out of different kinds. Say two students are friends if they both chose from the same type of fruit. Find the minimal so that it is possible that each student has exactly friends.