SOLUTION: Going into the final exam, which counts as two grades, Kendra has test scores of 84, 78, 64, and 88. What score does Kendra need on the final exam in order to have an average of 8

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Question 337170: Going into the final exam, which counts as two grades, Kendra has test scores of 84, 78, 64, and 88. What score does Kendra need on the final exam in order to have an average of 80?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Going into the final exam, which counts as two grades, Kendra has test scores of
84, 78, 64, and 88.
What score does Kendra need on the final exam in order to have an average of 80?
:
Let x = score she need to get an 80
:
It counts as two grades, call it 2x and set up the equation for 6 test scores
%28%282x+%2B+84+%2B+78+%2B+64+%2B+88%29%29%2F6 = 80
:
%28%282x+%2B+314%29%29%2F6 = 80
Mult both sides by sides by 6
2x + 314 = 6(80)
:
2x + 314 = 480
:
2x = 480 - 314
:
2x = 166
x = 166%2F2
x = 83 is the grade to get an 80 average