Answer:
7 miles / hour
Explanation:
I'm taking this to mean she walked 3.5 miles. She did this 1/2 hour.
Givens
d (distance ) = 3.5 miles
t (time) = 1/2 hour
r (rate) = ?
Formula
r = d/t
Solution
The easiest way to do this is to change the fractions to decimals.
t = 1/2 = 0.5 hours
r = 3.5 / 0.5
r = 7 miles per hour.