Final answer:
The relationship between the number of DVDs and the cost is proportional.
Step-by-step explanation:
In order to determine if the relationship between the number of DVDs and the cost is proportional, we need to see if the ratio of DVDs to cost is the same for both options.
Option 1:
Number of DVDs = 3
Cost = $22.50
Ratio of DVDs to cost = 3/22.50 = 1/7.50
Option 2:
Number of DVDs = 5
Cost = $37.50
Ratio of DVDs to cost = 5/37.50 = 1/7.50
Since the ratio is the same for both options, the relationship is proportional.