You are hiking on a trail that leads down from the top of a mountain. At 1 P. M. you are at an elevation of 6000 feet. At 5 P. M. you are at an elevation of 4800 feet. What is your mean hourly change in elevation?

Okay to start this out. You started hiking at 1 P. M. You are at an elevation of 6000 ft. At 5 PM You are at an elevation of 4800 feet. 6000 feet - 4800 feet = 1200 feet in 4 hours.

Make a ratio 4 (Hr) : 1200 Ft

3 (Hr) : 900 Ft

2 (Hr) : 600 Ft

1 (Hr) : 300 Ft

So at the end of the equation your hourly change is - 300 ft, because the elevation is going down.