Let's tackle this problem step by step.
1. Initial Altitude:
The plane starts at an altitude of 35,000 feet.
2. Descent:
The plane descends 12,000 feet from its initial height.
To find the new altitude after descending, we subtract the feet descended from the initial altitude:
[tex]\[
35,000 \text{ feet} - 12,000 \text{ feet} = 23,000 \text{ feet}
\][/tex]
So, after descending 12,000 feet, the plane is at 23,000 feet.
3. Climb:
Next, the plane climbs 9,000 feet from its current altitude of 23,000 feet.
To find the altitude after climbing, we add the feet climbed to the current altitude:
[tex]\[
23,000 \text{ feet} + 9,000 \text{ feet} = 32,000 \text{ feet}
\][/tex]
So, after climbing 9,000 feet, the plane is at 32,000 feet.
4. Descent to Land:
The final altitude to which the plane needs to descend to land is calculated from its current altitude, which is now 32,000 feet.
Since landing requires the plane to be at ground level, the plane needs to descend the entire 32,000 feet to reach 0 feet (ground level).
So, the plane needs to descend 32,000 feet to land.
