SOLUTION: if someone wanted an average grade of 90 and they base the grade on 4 tests and the first 3 scores were 84 93 and 88 what would the last test score grade have to be to get a total

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Question 148549: if someone wanted an average grade of 90 and they base the grade on 4 tests and the first 3 scores were 84 93 and 88 what would the last test score grade have to be to get a total average of 90?
85
88
92
or
95
Answer by mangopeeler07(462) About Me  (Show Source):
You can put this solution on YOUR website!
Set up an equation for the average: %2884%2B93%2B88%2Bx%29%2F4=90

Combine like terms:

%28265%2Bx%29%2F4=90

Multiply both sides by 4.

265%2Bx=360

Subtract 265 from both sides

x=95

So for the average grade to be 90, the person would have to get a 95.