According to the meaning of the question, it can be concluded that the total grade of the class is as follows: 4 1×85=3485 (points). When calculating, one student who missed the exam due to illness is included in the total number, then the actual average grade should be divided by the total grade of the class minus the students who missed the exam due to illness, that is:

3485÷(4 1- 1)

=3485÷40

=87. 125 (minimum)

Above 85 points: 87. 125-85=2. 125 (points)

You can also get an average score of 85 points, so that a classmate who is sick and absent from the exam can give less to everyone in the class. The actual average score is higher than 85. The formula is:

85 (41-1) = 2.125 (point)