The answer is (2.5, 8.75).
Explanation: First you want to find the unit rate. So if you look at the graph you see that one quart is equal to 3.5 dollars. This is your unit rate.
Next, do $8.75/$3.5. You want to divide because since you know the unit rate is 3.5, you want to find how much u have to multiply to get to 8.75. 8.75/3.5 is 2.5. Finally you want to find the quarts the customer bought so you do 2.5 x 1 since you increased by x2.5. If you put these two answers together on a graph you get (2.5, 8.75)
English is not my first language so I apologize if my answer is hard to understand.