To find the constant rate of the relationship, we need to use the formula to find the slope, which is the following:
Replace for two of the given pair of corresponding data, for example:
The constant rate of the relationship is 3.5. It seems like the relationship is a proportional relationship, we can describe it as follows:
Where k is the constant rate or constant of proportionality, that in this case is 3.5. The relationship can be described as:
It means that the cost for one hamburger is $3.5. Everytime you add an hamburger, the total cost will have an increase of $3.5.