The cost of candy bar is displayed in the table the proportional relationship between the costs and quality for candy bar b is represented by the equation y equals x which candy bar is the cheapest cost per bar inner one for candy bar a and inner two for candy bar b
Candy Bar A has a cost of $1 per bar, while Candy Bar B has a cost of $2 per bar.
Since the equation representing the proportional relationship between cost and quantity is y = x, we can see that for every increase in quantity (x), there is a corresponding increase in cost (y) by the same amount.
Using this information, we can see that Candy Bar A has the cheapest cost per bar, as it costs $1 per bar compared to Candy Bar B which costs $2 per bar.