Question

You are studying for your final exam on the semester. Up to this point, you received 3 exam scores of 99%, 80%, And 70%. To receive a grade of 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

Answer 1

Answer: The interval would be [71,107]

Step-by-step explanation:

Since we ave given that

Scores received in 3 exams are 99%, 80%, and 70%.

To receive a grade of B in the class, he must have an average exam score between 80% and 89% for all 4 exams for all 4 exams.

So, Minimum marks he needs for all 4 exams is given by

$80\times 4=320$

Maximum marks he needs for all 4 exams is given by

$89\times 4=356$

And his total marks in 3 exams is

$99+80+70\\\\=249$

Minimum marks he needs in final exam is given by

$320-249\\\\=71$

Maximum marks he needs in final exam is given by

$356-249\\\\=107$

Hence, the interval would be [71,107]

Answer 2

80*4=320
89*4=356
This is the range of the addition of all 4 scores.

99+80+70=249

320-249= 71
356-249= 107

[71, 100] would be the answer, unless you can get extra credit on the final.