Which year is it difficult to take the postgraduate entrance examination in Mathematics 98 and 20?
98 years. From 1987 to now, the year with difficult questions is 1998, and the average score is only 40. It should be noted that before 2002, the perfect score of mathematics for postgraduate entrance examination was only 100, and if the perfect score system was adopted, the average score was only 60. However, the year with difficult questions was not the year with the lowest score.