Answer: The graph is attached.
Explanation:
We must design a graph so that the x-axis represents the Time in hours and the y-axis represents the Height in feet.
The plane takes off from this point:
.
We know that the plane climbs steadily for 30 minutes (which is 0.5 hours) until it reaches 40000 feet. Then, we can identify another point; this is:

It travels at that altitude for 2 hours (which indicates a horizontal line) and then it begins to descend to land, giving us another point:

This takes 15 minutes (which is 0.25 hours) at a constant rate. Then, we get a final point:

Knowing these points, we can draw the graph (Observe the image attached)