Final answer:
Sonya's running distance can be found by setting up the equation x + 27 = 45, where x is the distance Sonya ran. By subtracting 27 from both sides, we find that x equals 18, and thus Sonya ran 18 miles.
Step-by-step explanation:
The student needs to establish an equation to determine the distance run by Sonya. Since Demetrius ran 27 miles more than Sonya and Demetrius ran a total of 45 miles, we can set up an equation to reflect this relationship.
Let Sonya's distance be represented by x. The equation would then be:
x + 27 = 45
This equation states that Sonya's running distance plus 27 miles equals the distance run by Demetrius, which is 45 miles. To solve for x, we subtract 27 from both sides of the equation:
x = 45 - 27
x = 18
Therefore, Sonya ran 18 miles.