If Nathan takes 40 minutes to walk 2.5 miles on a treadmill, we can start by finding his average speed:
Average speed = distance / time
In this case, distance is 2.5 miles and time is 40 minutes. However, we want to find how long it takes to walk each mile, so we need to express the distance and time in terms of one mile:
Distance per mile = 1 mile
Time per mile = x (what we want to find)
Using the equation for average speed and the distance and time per mile, we can write:
Average speed = distance per mile / time per mile
2.5 miles / 40 minutes = 1 mile / x
Simplifying this equation, we get:
x = 40 minutes / 2.5 = 16 minutes per mile
Therefore, it takes Nathan 16 minutes to walk each mile if he takes the same amount of time for each mile.