Answer:
+49 feet
Step-by-step explanation:
The inicial position that Suzie started her hike was 220 feet below sea level, so as this inicial position was negative, let's use the negative sign for it:
Inicial position = -220 feet
The final position of the hike was 171 feet below sea level, so:
Final position = -171 feet
So we calculate the change in elevation from the beginning to the end of the hike by making the difference between the final position and the inicial position:
Change in elevation = Final position - Inicial position = -171 - (-220) = -171 + 220 = +49 feet
The change in elevation was +49 feet (the positive sign indicates that the movement was upwards, in direction to "above sea level")
