Answer:
Mildred’s corrected report card average is 86%.
Step-by-step explanation:
First we will add the seven grades and divide by 7, to get the average.
[tex]\frac{SumOfSevenGrades}{7} =77[/tex]
=> Sum Of Seven grades = 539
Now, in this sum the English marks are added wrong. So we will adjust the sum by subtracting the wrong grade and adding the corrected grade.
Correct sum of seven grades =[tex]539-18+81 = 602[/tex]
Correct average = [tex]\frac{602}{7} =86[/tex]
Therefore, Mildred’s corrected report card average is 86%.