Final answer:
The distance from the mountain can be described using the linear function D = 0.1x, where D is the distance from the mountain and x is the time in minutes.
Step-by-step explanation:
To describe how far the ski-lift is from the mountain after x minutes, we can use a linear function. Let's call the distance from the mountain D and the time in minutes x.
Since the ski-lift travels at a constant speed of 0.1 miles per minute, the distance traveled is equal to the speed multiplied by the time: D = 0.1x.