Question

On two​ examinations, you have grades of 8787 and 8989. There is an optional final​ examination, which counts as one grade. You decide to take the final in order to get a course grade of​ A, meaning a final average of at least 90. a. What must you get on the final to earn an A in the​ course? b. By taking the​ final, if you do​ poorly, you might risk the B that you have in the course based on the first two exam grades. If your final average is less than​ 80, you will lose your B in the course. Describe the grades on the final that will cause this to happen.

Answer 1

Answer:

Explanation:

a.

Suppose that "x" is  your final exam grade.

Then you want:  (87  +  89  +  x ) / 3   ≥   90

(176 + x )/3   ≥   90

We then multiply the equation by 3 and get

176 + x ≥   270

Hence x ≥   (270-176)

we get:  x ≥  94

To get A Grade in a course, You must get at least a 94 on the final exam.

b.

If your final average is less than 80, You will lose your B in course

i.e   (87  +  89  +  x ) / 3 <  80

(176 + x )/3  <  80

We then multiply the equation by 3 and get

176 + x <   240

 Hence x <   (240-176)

we get:  x <  64

You will lose your "B" if your Final grade is less than 64