English: The demand curve, shown in blue is sloping downwards from left to right because price and quantity demanded are inversely related. This relationship is contingent on certain ceteris paribus conditions remaining constant. The supply curve, shown in orange intersects with the demand curve at price (Pe) = 80 and quantity (Qe)= 120. Pe i.e., 80 is the equilibrium price at which quantity demanded is equal to the quantity supplied. Similarly, Qe i.e., 120 is the equilibrium quantity. It is the quantity demanded and supplied at the equilibrium price. This the combination of the law of demand and supply provides us with the efficient allocation of goods in an economy.