Well maybe because the only thing that is different is the - and +
The figure is a right angle
Complementary = sum of 90 degrees
35 + 2x - 5 = 90
30 + 2x = 90
2x = 60
Solution: x = 30
The Mean would increase to 82.17 or a total increase of .17
You have 99 students and the avg is 82, therefore we can multiply 99*82 to get our total points
99*82=8118
We add a single score of 99 to our total points 8118+99= 8217
Then we add the student to the total number of students bringing it to 100 and divide our new total by the our new number of students.
8217/100 = 82.17
