Final answer:
To determine if a relationship is proportional, compare the ratio between the independent and dependent variables. In the first advertisement, the relationship is proportional, while in the second advertisement, it is nonproportional.
Step-by-step explanation:
To determine whether a relationship is proportional, we need to compare the relationship between the independent variable and the dependent variable. In a proportional relationship, the ratio between the two variables remains constant.
In the first advertisement, the car rental cost is $19.99 per day with no extra fees. We can represent this relationship as cost = 19.99 * number of days. Since the cost is directly proportional to the number of days, this is a proportional relationship.
In the second advertisement, the car rental cost is an initial fee of $9.99 plus $14.99 per day. We can represent this relationship as cost = 9.99 + 14.99 * number of days. Since the ratio between the cost and the number of days is not constant, this is a nonproportional relationship.