SOLUTION: You have grades of 81, 99, 95, 75 and 85 in your history class. You want to have at least an average of 89 in the class by report card time. What must you average on the next four

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Question 112607: You have grades of 81, 99, 95, 75 and 85 in your history class. You want to have at least an average of 89 in the class by report card time. What must you average on the next four tests for this to happen?
Answer by SHUgrad05(58) About Me  (Show Source):
You can put this solution on YOUR website!
Let n=the average on the next 4 tests:
81+99+95+75+85+4n/9=89 -> multiply through by 9
435+4n=801
4n=366
n=91.5
You must average 91.5 on the next 4 tests to average 89 by report card time