SOLUTION: Going into the final exam which counts as two-thirds of the final grade, Mark has test scores of 86, 80, 84, and 90. What score does Mark need on the final in order to earn a B, w

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Question 5064: Going into the final exam which counts as two-thirds of the final grade, Mark has test scores of 86, 80, 84, and 90. What score does Mark need on the final in order to earn a B, which requires an average score of 80? What does he need to earn an A, which requires a score of 90? Thanks Again. You are a great help.
Answer by rapaljer(4671) (Show Source):
You can put this solution on YOUR website!
Average his four grades together by adding and dividing by 4:

Let x = grade on the final, which counts as two grades, whereas his average on the other tests, which is 85, counts as a single grade.

Solve the following equations:

For a B in the class:

Multiply both sides by 3:
85 + 2x = 240
2x = 155
x= 77.5

For an A in the class:

Multiply both sides by 3:
85 + 2x = 270
2x = 185
x= 92.5

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