Please help me with the answer to the Free Response on USATestPrep!!

Question:

Determine the average rate of change for the following questions. Show your work.

1. It takes a rocket 30 seconds to travel 1 mile above the earth’s surface and 1 1/2 minutes to travel 6 miles. What is the rate of change per second for the entire trip?

2. What is the rate of change for the same rocket to complete its trip after the first mile?

3. Graph both answers; show the rate of change for the first mile and the rate of change after the first mile. (y = 2 1/2 units equal one mile, x = one unit equals 10 seconds)