Final answer:
The overall change in Sally's elevation after hiking is a decrease of 128 feet from her starting elevation.
Step-by-step explanation:
Sally starts off at an elevation of 324 feet. Her first change in elevation is a descent to 201 feet. To calculate the change, we subtract 201 from 324, resulting in a descent of 123 feet. Next, Sally climbs to an elevation that is 55 feet higher than her starting point which is 324 + 55, giving us an elevation of 379 feet. This is a change of 379 - 201 = 178 feet. Finally, Sally descends 183 feet which leaves her at an elevation of 379 - 183 = 196 feet.
The overall change in elevation can be found by comparing her final elevation with her starting elevation. Therefore, her overall change is the final elevation of 196 feet minus her starting elevation of 324 feet, which equals to -128 feet. This means Sally is 128 feet lower than where she began.