In a class in which the final course grade depends entirely on the average of four equally weighted 100-point tests, Erica has scored 86, 79

Question

In a class in which the final course grade depends entirely on the average of four equally weighted 100-point tests, Erica has scored 86, 79, and 85 on the first three. What range of scores on the fourth test will give Erica a C for the semester (an average between 70 and 79, inclusive)? Assume that all test scores have a non-negative value.

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Faith 3 days 2021-10-09T22:03:59+00:00 1 Answer 0

Answers ( )

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    2021-10-09T22:05:28+00:00

    Answer:

    Erica must score between 30 and 66 to obtain a grade average of C.  

    Step-by-step explanation:

    We are given the following ion the question:

    Erica’s score:

    86, 79, and 85

    To get a grade C, the average score of Erica must lie between 70 and 79.

    Formula:

    Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}

    Let x be the score on fourth test.

    Thus, we can write:

    70\leq \dfrac{86+79+85+x}{4}\leq 79\\\\280\leq 250+x\leq 316\\280-250\leq x \leq 316-250\\30\leq x\leq 66

    Thus, Erica must score between 30 and 66 to obtain a grade average of C.

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45:7+7-4:2-5:5*4+35:2 =? ( )