Question

8 students are enrolled in a competition. they all solve the same 8 qs. after correction, it can be seen that each problem has been correctly solved by exactly 5 students. show that there are 2 students who, together, have solved all the problems?

Answer 1

Let's label the 8 questions as Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8.

Let's label the 8 students as A, B, C, D, E, F, G, and H.

Since each problem has been correctly solved by exactly 5 students, we can say that the following is true:

Q1: A, B, C, D, E

Q2