Answer: The family travel at 45 miles per hour.
Explanation:
Since we have given that
Number of miles away her grandmother lives = 45 miles
Time taken by her and her family = 1 hour
We need to find the rate that the family traveled.
Here, unit rate stands for "Speed at which she and her family travelling">
As we know the formula for "Speed":
Hence, the family travel at 45 miles per hour.