Question

You are studying for your final exam of the semester. Up to this point, you received 3 exam scores of 96%, 77%, and 74%. To receive a grade B in the class, you must have an average exam score between 80% and 89% for all 4 exams including the final.
Find the widest range of scores that you can get on the final exam in order to receive a grade of B for the class. Use interval notation.

A. [67, 100]
B. [73, 100]
C. [70, 71]

Answer 1

((96 + 77 + 74 + x) / 4) > 80
(( 247 + x) / 4) > 80
247 + x > 80 * 4
247 + x > 320
x > 320 - 247
x > 73

((96 + 77 + 74 + x) / 4) < 89
((247 + x) / 4) < 89
247 + x < 89 * 4
247 + x < 356
x < 356 - 247
x < 109...but since it only goes to 100, I suppose it is 100

answer is B