Answer:
I don't know what you mean by "explain in words", but I'm assuming you were referring to point b.
Step-by-step explanation:
You have to see that the rate of change, the "speed" at which her elevation decreases is 0.25 feet/s, such that in 8 seconds she went down by 2 feet.
Thus, until 50, you just gotta do the calculation for that speed. You notice that she needs to go 30 feet, at a speed of 0.25 feet per second, or 1 foot every 4 seconds.
