3.1

Part of 2014 Saudi Arabia Pre-TST

Problems(1)

14 students in a 3 hour test consisting on 15 short problems

Source: 2014 Saudi Arabia Pre-TST 3.1

14

students who have particiated to a

3

hour test consisting on

15

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

5