Question

To receive a C grade, a student must average more than a 77 but less than 85. If Emma received a C in the course and had five grades of 74,83,73,67,and 85 before taking the final exam, what were the possible grades for her final there were 100 points. (Assume all six grades are weighted equally and let x represent the unknown score)

Answer 1

The sum of her first 5 scores is 382

6*77 = 462
6*85 = 510

So the last score must satisfy

462 < 382+x < 510
80 < x < 128

So, any score above 80 will get her a C grade.