SOLUTION: What grade must a student make on his fourth math test in order to have an average score of 90 if his other grades are 86, 85, and 94?

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Question 1064400: What grade must a student make on his fourth math test in order to have an average score of 90 if his other grades are 86, 85, and 94?
Answer by Edwin McCravy(20059) About Me  (Show Source):
You can put this solution on YOUR website!
%2886%2B85%2B94%2Bx%29%2F4%22%22=%22%2290

Multiply both sides by 4 to eliminate the fraction:

86%2B85%2B94%2Bx%22%22=%22%22360

You finish solving for x.

Edwin