Louis is walking at 4 mph. If Louis can walk 2 miles in 30 minutes, she can then walk 4 miles in an hour if you double the amount of time she is walking from 30 to 60, so you would also double the distance. She is walking at 4 miles per hour.
See photo for worked out solution.
Hope this helps!
Arjun should have divided both sides of the equation by 7 instead of multiplying.
