# Demand

We begin our study of markets by examining the behavior of buyers. To focus our thinking, let’s keep in mind a particular good – ice cream

The Demand Curve: The Relationship between Price and Quantity Demanded

Quantity demanded the amount of a good that buyers are willing and able to purchase.

Law of demand the claim that, other things equal the quantity demanded of a good falls when the price of the good rises.

Demand schedule a table that shows the relationship between the price between the price of a good and the quantity.

The quantity demanded of any good is the amount of the good that buyers are willing and abler to purchase. As we will see, many things determine the quantity demanded of any good, but when analyzing how markets work, one determinant plays a central role – the price of the good. If the price of ice cream rose to \$20 per scoop, you would buy less ice cream. You might buy frozen yogurt instead. If the price of ice cream fell to \$ 0.20 per scoop, you would buy more. Because the quantity demanded falls as the price rises and rises as the price falls, we sat that quantity demanded is negatively related to the price. This relationship between price and quantity demanded is true for most goods in the economy and, in fact, is so pervasive that economists call it the law of demand: good falls, and when the price falls, the quantity demanded rises.

Catherine buys ice cream cones each month at different prices of ice cream. If ice cream is free, Catherine eats 12 cones per month. At \$0.50 per cone, Catherine buys 10 cones each month. As the price rises further, she buys fewer and fewer cones. When the price reaches \$ 3.00 Catherine doesn’t buy any ice cream at all. The relationship between the price of a good and the quantity demanded, holding constant everything else that influences how much consumers of the good want to buy.

By convention, the price of ice cram is on the vertical axis and the quantity of ice cream demanded is on the horizontal axis. The downward sloping line relating price sand quantity price and quantity demanded is called the demand curve.

Market Demand versus Individual Demand:

Demand curve a graph of the relationship between the price of a good and the quantity demanded.

The demand curve shows an individual’s demand for a product. To analyze how markets work, we need to determine the market demand, the sum of all the individual demands for a particular food or service.

The demand schedules for ice cream of two individuals – Catherine and Nicholas. At any price, Catherine’s demand schedule tells how much ice cream she buys, and Nicholas’s demand schedule tells us how much ice cream he buys. The market demand at each price is the sum of the two individual demands.

The demand curves that correspond to these demand schedules. Notice that we sum the individual demand curves horizontally to obtain the market demand curve. That is, to find the total quantity demanded at any price, we add the individual quantities found on the horizontal axis of the individual demand curves. Because we are interested in analyzing how markets work, we will work most often with the market demand curve. The market demand curve shows how the total quantity demanded of a good varies as the price of the good varies, while all the other factors that affect how much consumers want to buy are held constant.