Final answer:
Marcia's final displacement is 2.0 km north.
Step-by-step explanation:
To find the final displacement of Marcia, we can add up her individual displacements in each direction. Starting with her run of 8.0 km west, her displacement in the west direction would be -8.0 km. Next, her run of 5.0 km south gives her a displacement of -5.0 km in the south direction. Her run of 8.0 km east contributes a displacement of +8.0 km in the east direction. Finally, her run of 7.0 km north adds a displacement of +7.0 km in the north direction. To find the final displacement, we add up all these displacements: (-8.0 km) + (-5.0 km) + (+8.0 km) + (+7.0 km) = +2.0 km. Therefore, Marcia's final displacement is 2.0 km north.