SOLUTION: 8. The final grade for a particular course is calculated by dividing total points earned by total points available. There are 120 points available in the first half of the course,

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Question 182997: 8. The final grade for a particular course is calculated by dividing total points earned by total points available. There are 120 points available in the first half of the course, and 140 points in the second half of the course. If a student earns 81% in the first half of the course, how many points must the student earn in the second half in order to earn an 80% B final grade?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Let's start by seeing what the student earned in the first half of the course.
He/she earned 81% of 120 points. That's 0.81(120) = 97.2 points.
So we let x = the percentage that the student must earn in the second half of the course so that the the final grade is 80% of 260 (120+140) points., so...
Take the total points earned (97.2+x(140)) and divide by the total points available (260) and this is to equal 80% (0.8).
%2897.2%2B140x%29%2F260+=+0.8 Multiply both sides by 260.
97.2%2B140x+=+0.8%28260%29
97.2%2B140x+=+208 Subtract 97.2 from both sides.
140x+=+110.8 Divide both sides by 140.
x+=+0.791429 or x = 79.1429%
The number of points the student needs in the second half is 79.01429% of 140.
highlight%280.791429%28140%29+=+110.8%29points.
Check:
The number of points earned in the first half (97.2) plus the number of points earned in the second half (110.8) all divided by the total points available (260) should equal 0.8 or 80%.
%2897.2%2B110.8%29%2F260+=+0.8 or 80% OK!