Quantitative Literacy Practice Exam 2025 – Comprehensive All-in-One Guide to Exam Success!

To determine the grade Sarah needs on her fifth test to achieve an average of 80.2, you first calculate the total points she must earn across all five tests. An average is computed by dividing the total score by the number of tests, so rearranging the formula for average, we see that:

Total score needed = Desired average × Number of tests.

In this case, the desired average is 80.2, and there are five tests, so:

Total score needed = 80.2 × 5 = 401.

Next, you sum the scores of Sarah's first four tests:

79 + 73 + 77 + 89 = 318.

Now, to find out what Sarah needs on her fifth test, you subtract the sum of her first four tests from the total score needed:

Grade on fifth test = Total score needed - Sum of first four tests = 401 - 318 = 83.

Thus, the grade Sarah needs on her fifth test to meet her average goal of 80.2 is indeed 83, making this the correct answer. This method demonstrates how to approach problems involving averages and required performance to meet specific academic targets.