To determine which store has the better buy, we need to compare the cost per ounce from Store A (as shown in the graph) with Store B's cost per ounce given by the equation \( y = 0.13x \).
Next, we calculate the cost per ounce for Store A based on the four points provided:
- At \( x = 0 \text{ ounces} \): The cost is \( y = 0.00 \) (not useful for comparison).
- At \( x = 8 \): The cost is \( y = 0.80 \), so the cost per ounce is \( \frac{0.80}{8} = 0.10 \text{ dollars per ounce} \).
- At \( x = 15 \): The cost is \( y = 1.50 \), so the cost per ounce is \( \frac{1.50}{15} = 0.10 \text{ dollars per ounce} \).
- At \( x = 30 \): The cost is \( y = 3.00 \), so the cost per ounce is \( \frac{3.00}{30} = 0.10 \text{ dollars per ounce} \).
For Store B, the cost per ounce is directly given by the equation:
- When \( x = 1 \), \( y = 0.13 \cdot 1 = 0.13 \) dollars per ounce.
- Therefore, Store B's cost per ounce is \( 0.13 \) dollars.
Now let's compare the two stores:
- Store A cost per ounce: $0.10
- Store B cost per ounce: $0.13
Now we find the difference:
- Store B is more expensive, as $0.13 - $0.10 = $0.03
Thus, Store A has the better buy by $0.03 per ounce.
The correct response is: Store A has the better buy by $0.03 per ounce.