We want to study the change in Marianna's average score in social studies.
We will see that the change in her average is given by a decrease of 1.7 points or a decrease by the 2% of her initial average score.
The information we have is:
She initially had an average of 84.6
The final average is 82.9
There are multiple ways of studying the change, let's show the two more common ones.
Direct difference:
This is given by the direct difference between the final score and the initial score, this gives:
82.9 - 84.6 = -1.7
Meaning that the average decreased by 1.7 points.
Percentage difference.
If the initial average represents the 100%, then the percentage that the final average represents is given by:
(82.9/84.6)*100% = 98%
So we can say that her average decreased a 2% since the last exam.
If you want to learn more, you can read:
https://brainly.com/question/17645631
