Final answer:
The equilibrium price of cold brew in an unregulated competitive market is where the supply and demand curves intersect, adjusting automatically to changes like a reduced coffee supply from events like a frost in Brazil.
Step-by-step explanation:
In a competitive market without government regulations, the equilibrium price of cold brew per cup is determined by the intersection of the supply and demand curves. This point reflects the price at which the quantity demanded by consumers equals the quantity supplied by producers. If an external event, such as a frost damaging the coffee crop in Brazil, leads to a decreased supply of coffee, the supply curve shifts to the left, resulting in a higher equilibrium price. Coffee lovers may continue to purchase cold brew despite the price increase, while others may substitute coffee with alternatives like tea or soft drinks. These mechanisms ensure that market adjustments happen efficiently without the need for direct governmental intervention.