Answer: 9 miles per week
Step-by-step explanation:
You divide the two values given to get 63/7 = 9.
We can think of it as if it was a ratio 63 miles: 7 weeks. Dividing both parts of that ratio by 7 will turn the "7 weeks" into "1 week".
You can check the answer by multiplying the 9 miles per week with the 7 weeks to get 9*7 = 63 miles total.