Solution:
1. Given:
- The hiker's speed is such that each mile takes 15 minutes.
2. Define the function:
- Let f(m) represent the time in minutes it takes to walk m miles.
- Since each mile takes 15 minutes, we have:
f(m) = 15m
3. The function f(m) gives the total time taken in minutes based on the number of miles m walked.