SOLUTION: In a class in which the final course grade depends entirely on the average of four equally weighted 100-point tests, Erica has scored 94 94 , 89 89 , and 76 76 on the fir

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Question 1133371: In a class in which the final course grade depends entirely on the average of four equally weighted 100-point tests, Erica has scored 94
94
, 89
89
, and 76
76
on the first three. What range of scores on the fourth test will give Erica a C for the semester (an average between 70
70
and 79
79
, inclusive)? Assume that all test scores have a non-negative value.
Express your answer in interval notation.






Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
--------------
Erica has scored 94
94
, 89
89
, and 76
76
on the first three.
-------------

Say like this:
Erica has scored 94, 89, and 76 on the first three.

Her average of FOUR scores if #4 is score x, would be %28x%2B94%2B89%2B76%29%2F4.

--
%28x%2B259%29%2F4

Grade for C is between 70 and 79 inclusive.
70%3C=%28x%2B259%29%2F4%3C=79
280%3C=x%2B259%3C=316

280-259%3C=x%3C=316-259

highlight%2821%3C=x%3C=57%29

Would this make sense for the minimum score?
%2894%2B89%2B76%2B21%29%2F4=70
Okay