SOLUTION: "Your grades are 76, 90, 85 and 87. If the next grade received counts twice, what grade do you need to maintain an average of 84 in the class?"

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Question 86328: "Your grades are 76, 90, 85 and 87. If the next grade received counts twice, what grade do you need to maintain an average of 84 in the class?"
Found 3 solutions by stanbon, ankor@dixie-net.com, scott8148:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
"Your grades are 76, 90, 85 and 87. If the next grade received counts twice, what grade do you need to maintain an average of 84 in the class?"
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There will be five grades.
Let the missing grade be "x".
EQUATION:
(76+90+85+87+2x)/5 = 84
(338 + 2x) = 420
2x = 82
x=41 (You need a 41 on the next test)
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Cheers,
Stan H.

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
"Your grades are 76, 90, 85 and 87. If the next grade received counts twice, what grade do you need to maintain an average of 84 in the class?"
:
Let grade required to be = x,
:
That would give you a total number of grades of 6
:
%28%2876+%2B+90+%2B+85+%2B+87+%2B+x+%2B+x%29%29%2F6 = 84
:
Multiply equation by 6 and you have:
76 + 90 + 85 + 87 + 2x = 504
:
338 + 2x = 504
:
2x = 504 - 338
:
2x = 166
:
x = 166/2
:
x = 83 required
:
Check solution using a calculator

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
let x equal the grade ... you need an 84 average, so (76+90+85+87+x+x)/6=84 ... 338+2x=84*6 ... 2x=504-338 ... x=83