The correct average of the test is 74%.
Average:
Average means the middle value of a set of numbers.
And it can be calculated by the total of the numbers divided by how many numbers there are.
Given:
Mr. MacDonald recorded the test mark for his eight grade class of 25 students he used the marks recorded to calculate the average to be 72 Sandra's marks of 86 was incorrectly marked as 36.
Number of students = 25
Average mark of the students = 72
Incorrect mark = 36.
Correct mark = 86.
So, let us consider x is the sum of all grades.
Then,
=> x / 25 = 72
=> x = 1800 = the sum of all the grades
=> 1800 - 36 + 86 = 1850
=> 1800 / 25 = 74%
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