SOLUTION: A students grades in a course is the average of 4 test grades and a final exam that is worth 3 times as much as each test. Suppose a student has test grades of 91,89,78,92. Write a

Algebra ->  Average -> SOLUTION: A students grades in a course is the average of 4 test grades and a final exam that is worth 3 times as much as each test. Suppose a student has test grades of 91,89,78,92. Write a      Log On


   

Question 830003: A students grades in a course is the average of 4 test grades and a final exam that is worth 3 times as much as each test. Suppose a student has test grades of 91,89,78,92. Write an equation where x is the students grade and y is the students average. I am having a hard time coming up with the answer for why? I don't understand how they got the answer for it. I come close but not exact.
Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
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y = (1*91 + 1*89 + 1*78 + 1*92 + 3x)/7
y = (350 + 3x)/7
y = (3/7)x + 350/7
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answer:
y = (3/7)x + 50
where:
x = final exam grade (0 to 100)
y = course grade (0 to 100)
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