Final answer:
If buyers anticipate higher future prices for gasoline, this results in an increase in both the current price of gasoline and the quantity supplied today, creating a situation where the quantity supplied may exceed the quantity demanded.
Step-by-step explanation:
If buyers expect that the price of gasoline will be higher in the future, economic theory suggests that the price of gasoline today rises as people may buy more now to avoid paying higher prices later. Concurrently, the quantity supplied today increases, because suppliers want to take advantage of the higher price to sell more gasoline, as this increases their profits. As prices rise above the equilibrium, the quantity of gasoline supplied typically exceeds the quantity demanded, resulting in an excess supply or a surplus. This is illustrated when the price of gasoline increases to $1.80 per gallon, leading to an increase in the quantity of gasoline supplied from 600 to 680 gallons while the quantity demanded drops to 500 gallons.