SOLUTION: this one has me stumped. I don't know why, I usually can get averages, but my mind is stuck here: 8. The final grade for a particular course is calculated by dividing total poin

Algebra ->  Average -> SOLUTION: this one has me stumped. I don't know why, I usually can get averages, but my mind is stuck here: 8. The final grade for a particular course is calculated by dividing total poin      Log On


   

Question 183117: this one has me stumped. I don't know why, I usually can get averages, but my mind is stuck here:
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?
thanks for the help.
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
this one has me stumped. I don't know why, I usually can get averages, but my mind is stuck here:
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? 



81% or .81 of the 120 points available in the first half 
of the course is 97.2 points.

Let x = the number of points to make in the second half

Then total points made in both halves will be 97.2 + x

The total points available in both halves of the course is 120 + 140 = 260



We substitute .8 (the decimal equivalent of 80% for the Average

+matrix%281%2C3%2C+.8%2C+%22=%22%2C+%2897.2%2Bx%29%2F260++%29

Can you solve that equation for x?  If not post again.

Answer: 110.8

Edwin