Question 567475: Going into the final exams, which will count as two-thirds of the final grade, Mike has test scores of 86,80,84, and 90. What score does Mike need on the final in order to earn a B, whuch requires an average score of 80? What does he need to earn an A, which requires an average of 90?
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! Going into the final exams, which will count as two-thirds of the final grade, Mike has test scores of 86,80,84, and 90. What score does Mike 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 an average of 90?
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Given:
final exam counts as 2/3 of the final score
previous test scores count as 1/3 of the final score
let x=score needed on final to get a B or A grade
..
(86+80+84+90)/4=85 (average of previous test scores)
To get a B grade:
85/3+2x/3=80
85+2x=240
2x=240-85=155
x=155/2=77.5
..
To get an A grade:
85/3+2x/3=90
85+2x=270
2x=270-85=185
x=185/2=92.5
..
ans:
Final score needed to earn an A: 92.5
Final score needed to earn a B: 77.5
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