Nikhil biked 54 miles in 4.5 hours
Since the speed in 4.5 hours = 54 miles
Then we need to find the speed in 1 hour, for this divide 54 by 4.5
Speed in 1 hour is the Nathan average speed in miles per hour
So, Nathan average speed in miles per hour is 12 miles per hour
Answer: 12 miles per hour