Aplane takes off and climbs steadily for 30 minutes until it reaches 40,000 feet. it travels at that altitude
for 2 hours until it begins to descend to land, which it takes 15 minutes at a constant rate. draw a graph
of the situation

The graph is attached.

Step-by-step 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)

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)