A(x)=(2x+100)/x = 2+(100/x).
As x increases A decreases. When x=1 the average cost is maximum at $102 (the cost of the only DVD). For x=2, the cost drops to $52. When x is very large A approaches $2. That is, the average cost per DVD decreases as more and more movies are made for rent.
It should encourage the executives to make more movies for rent, and perhaps expand their premises to accommodate more DVDs.
As an employee, I could create or maintain a catalogue of movie titles and record how many DVD copies of each movie were held in stock. I could also report to the executives about what new movies were popular, and encourage making DVDs of them.
There is only one value for x where A would be undefined, that is, x=0.
That could only occur if no DVDs were made.