To determine the year when the price per bag of cookies was $4 using the curve described, you would need to look for the point on the graph where the y-coordinate (price in dollars) equals 4.
The x-axis corresponds to time in years since 2007. You would locate the intersection of the horizontal line at $4 with the curve representing the price over time.
Once you find that intersection point, you can identify the corresponding year. For example, if the intersection occurs at the point on the graph that aligns with the year 2010 on the x-axis, then the price of the cookie bag was $4 in 2010.
Unfortunately, as I don't have access to visual images, I would recommend looking at the graph closely to find that specific intersection point.