11. Members of the student council are conducting a fundraiser by selling school calendars. After selling 80 calendars, they had a loss of $ 360. After selling 200 calendars, they had a profit of $600. Write an equation that describes the relation between y, the profit or loss, and x, the number of calendars sold. How much profit did they make from selling each calendar? How much would they have lost if they had sold no calendars?