Both the table and the graph show the total quantity of apples that would
be demanded at various prices, ceteris paribus. For example, row W
indicates that if the price of apples were $60 per bushel, consumers would
desire to purchase 65 000 bushels of apples per year, holding constant the
values of the other variables that affect quantity demanded. The demand
curve, labelled D, relates quantity of apples demanded to the price of
apples; its negative slope indicates that quantity demanded increases as
price falls.
A second method of showing the relationship between quantity
demanded and price is to draw a graph. The five price–quantity
combinations shown in the table are plotted in Figure 3-1. Price is
plotted on the vertical axis, and the quantity demanded is plotted on the
horizontal axis.
The curve drawn through these points is called a demand curve It
shows the quantity that consumers would like to buy at each price. The
negative slope of the curve indicates that the quantity demanded
increases as the price falls. Each point on the demand curve indicates a
single price–quantity combination. The demand curve as a whole shows
something more.
The demand curve represents the relationship between quantity demanded and price, other
things being equal; its negative slope indicates that quantity demanded increases when price
decreases.When economists speak of demand in a particular market, they are
referring not just to the particular quantity being demanded at the
moment (i.e., not just to one point on the demand curve) but to the entire