Question

You are studying for your final exam of the semester. up to this point, you received 3 exam scores of 76%, 99%, and 86℅. to receive a grade of A in the class, you must have an average exam score between 90% and 100% 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 A for the class. use interval notation.

[91,100]
[99,100]
[96,97]

Answer 1

Minimum overall average for a grade of A is 90. Setting up the formula for this average results in:

76+99+86+s
----------------- = 90
4

Then, 76+99+86+s = 360, and 261 + s = 360. Solving for s, s = 99.
Thus, 99 is the lowest grade you'd have to earn to receive a grade of A in this course.

Expressed in interval notation, that 'd be [99,100].

Check: Does (76+99+86+99)/4 come out to 90? Yes.