SOLUTION: Use Interval notation to express the range.. On the first of four exams, your grades are 78, 86, 69 and 79. You are hoping to earn a C in the course. this will occur if the aver

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Use Interval notation to express the range.. On the first of four exams, your grades are 78, 86, 69 and 79. You are hoping to earn a C in the course. this will occur if the aver      Log On


   

Question 378119: Use Interval notation to express the range..
On the first of four exams, your grades are 78, 86, 69 and 79. You are hoping to earn a C in the course. this will occur if the average of your five exam grades is greater than or equal to a 70 and less than an 80. What range of grades on the fifth exam will result in earning a C?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Aim for the middle?
.
.
.
The average is equal to,
A=%2878%2B86%2B69%2B79%2BX%29%2F5
where X is the final grade.
70%3CA%3C80
70%3C%2878%2B86%2B69%2B79%2BX%29%2F5%3C80
350%3C%28312%2BX%29%3C400
highlight%2838%3CX%3C88%29