SOLUTION: The grading scale for a C in Amy's biology class is an average on tests between 70% and 80%, inclusive. Amy has 64%,84%,and 78%on the first three tests this semester. What range of

Question 817448: The grading scale for a C in Amy's biology class is an average on tests between 70% and 80%, inclusive. Amy has 64%,84%,and 78%on the first three tests this semester. What range of scores on the fourth test would give her a C?
Answer by LinnW(1048) (Show Source): You can put this solution on YOUR website!
( 64 + 84 + 78 + x )/4 >= 70 is the equation for obtaining at least a C
( 226 + x )/4 >= 70
Multiply each side by 4
226 + x >= 70*4
226 + x >= 280
Subtract 226 from each side.
x >= 54
To determine the maximum value of x
we need to solve
( 64 + 84 + 78 + x )/4 <= 80
The rest is left for the student.
RELATED QUESTIONS
to earn a B in your algebra class you must achieve an unrounded test average between 84... (answered by ewatrrr)

In a class in which the final course grade depends entirely on the average of four... (answered by josgarithmetic)

In a class in which the final course grade depends entirely on the average of four... (answered by jorel555)

In a class in which the final course grade depends entirely on the average of four... (answered by greenestamps)

In a class in which the final course grade depends entirely on the average of four... (answered by math_helper)

What are the probabilities that a student will receive an A, B, C, D, and F in a class?... (answered by stanbon)

In order for brady to earn a B in his biology course, his test scores must average at... (answered by josgarithmetic)

Jeo has scores of 65,94 and 88 on his biology tests, and now is getting ready for the... (answered by checkley79)

In a class in which the final course grade depends entirely on the average of four... (answered by Boreal)