Definition of demand

The Allocation of Resources – Demand

Definition of Demand 📈

Demand is the quantity of a good or service that consumers are willing and able to buy at a given price, during a specific period. It is a key concept in economics because it helps explain how resources are allocated in a market.

Key Terms

• Quantity demanded – the exact amount a consumer wants to buy at a particular price.
• Willingness to pay – how much a consumer values a good, reflected in the price they are ready to pay.
• Ability to pay – the consumer’s financial capacity to purchase the good.
• Demand curve – a graph showing the relationship between price and quantity demanded.

Analogy: The Grocery Store Line 🍎

Imagine a grocery store with a single checkout line. The price of a pack of apples is $2. If the price drops to $1, more shoppers will want to buy apples, so the line gets longer. This line length is like the quantity demanded. The higher the price, the shorter the line – fewer people want to buy apples. This simple picture shows how price influences demand.

Mathematical Representation

The demand function can be written as:

$$Q_d = f(P, I, T, P_s, L)$$

Where:

• $P$ – price of the good
• $I$ – consumer income
• $T$ – tastes and preferences
• $P_s$ – prices of related goods (substitutes or complements)
• $L$ – number of consumers (population)

Real‑World Example: Smartphones 📱

When a new smartphone model is released at a high price, only a few consumers can afford it, so the quantity demanded is low. If the price is reduced by a discount, more people will buy it, increasing the quantity demanded. This demonstrates the inverse relationship between price and quantity demanded.

Demand vs. Supply

1. Demand focuses on buyers and their willingness to purchase.
2. Supply focuses on sellers and their willingness to produce.
3. Both interact to determine the market equilibrium price and quantity.

Summary Table of Demand Factors

Quick Check

1️⃣ If the price of a movie ticket rises, will the quantity demanded increase or decrease?
2️⃣ How does an increase in consumer income affect the demand for luxury cars?
3️⃣ What happens to demand when a cheaper substitute (e.g., a new streaming service) becomes available?