14 students in a 3 hour test consisting on 15 short problems
Source: 2014 Saudi Arabia Pre-TST 3.1
September 13, 2020
combinatorics
Problem Statement
There are students who have particiated to a hour test consisting on short problems. Each student has solved a different number of problems and each problem has been solved by a different number of students. Prove that there exists a student who has solved exactly problems.