Answer: 0.66 hours per mile
Explanation:
You know that in 4 hours Addison walked 6 miles.
Now, you need to calculate the amount of hours she walked in 1 mile.
Let be "x" the amount of hours she walked in 1 mile.
Then, to calculate the value of "x" you need to multiply 1 mile by 4 hours and divide by 6 miles:

≈

Therefore, her walking rate in hours per mile was:
0.66 hours per mile