Mr. Zorn had skated total 17 miles.
Step-by-step explanation
The length of the exercise trail around the Westwood park is 3 miles.
Mr. Zorn is skating around the trail 5 and 1/2 times.
So, the distance skated in 5 times

and the distance skated in
of the trail

Thus, the total distance he had skated will be:
(Rounded to the nearest mile)