Answer:
23316ft
Explanation:
in this problem, we are expected to solve for the change in height of the Appalachian Mountains
given that
the initial height was = 30,000 feet.
the current height is=6,684 feet.
Due to erosion the change/difference in height is give as
change/difference=30000 -6684
change/difference=23316ft
this means that for millions of years ago 23316ft of Appalachian Mountains have been eroded