SOLUTION: if you have 78 90 68 and 83 what do you need to get an average of 80

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Question 417043: if you have 78 90 68 and 83 what do you need to get an average of 80
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
I'll assume you mean by one additional test score.
(78+90+68+83+x)/5=80
(319+x)/5=80 cross multiply
319+x=80*5
319+x=400
x=400-319
x=81 ans. for the test score to maintain an 80 average.
Proof:
(78+90+68+83+81)/5=80
400/5=80
400=400