A climber is on a hike. After 2 hours he is at an altitude of 300 feet. After 1 point 6 hours, he is at an altitude of 500 feet. If the hiker were to continue hiking
uphill, what is the altitude of the hiker after 12 hours?

Average rate of change =

(change in height during some time) / (length of time for the change).

Change in height = (700 feet - 400 feet) = 300 feet

Time for the change = (6 hours - 2 hours) = 4 hours

Average rate of change = (300 feet) / (4 hours) = 75 feet per hour

nope.   happens to me as well.

-aparri