Answer: The change in height is 30 1/4 feet.
Solution:
Change in height: h=?
The car starts by going up 80 and one half feet:
h=+80 1/2 feet
Then the car goes down 50 and one fourth feet:
h=80 1/2 feet - 50 1/4 feet
h=80 2/4 feet - 50 1/4 feet
h= 80-50 2/4-1/4 feet
h=30 (2-1)/4 feet
h=30 1/4 feet