Answer:
Independent: y
Dependent: b
Explanation:
In the scenario being described the Independent variable would be y (Nate's grandmother's age) while the Depenent variable would be b (number of boxes of candles Nate will purchase). This is because the number of boxes of candles that Nate will purchase relies on his grandmother's age, meaning that it depends on variable b in order to determine its own value. On the other hand Nate's grandmothers age does not depend on anything in order to have a value.