Answer: 200 ft per hour
Explanation:
Given : You are hiking on a trail that leads to the top of a mountain.
At 12 P.M. you reach an elevation of 3700 feet. At 4 P.M. you reach an elevation of 4500 feet.
The formula for the mean hourly change in elevation is :-

From the given information, the change in elevation=4500 ft-3700 ft= 800 ft
Time taken = 4 hours [From 12 pm to 4 pm]
Now, Mean hourly change in elevation=

Hence, the mean hourly change in elevation = 200 ft