There are 40 students in a class taking math exams at the same time. Assuming that the average score of this test paper is 80, how many students fail at most?
Solution: If at most X students fail (less than 60 points), the number of students who pass is (40-x).
100(40-x)+59x≥40×80，
Solution: x in 0 ≤ 465438+800.
∵x is an integer,
X. max 19.
So the answer is: 19.