NCERT Class 9 Social Science Understanding Society India and Beyond Part 1 Chapter 09 The Price Puzzle What Drives the Market PDF Download

Chapter 9: The Price Puzzle: What Drives the Market

The Big Questions

1. What are the factors that influence the demand for and supply of goods and services in a market?
2. How are prices of goods and services determined through demand and supply interactions?
3. What is market equilibrium, and does it exist in the real world?
4. How and why does the government intervene in the market?

What happens if the mangoes your parents bought last week are now half the price? Why are vegetables expensive in the morning but are cheaper in the evening? Or why does the price of onions seem to change every few months? Why does the same flight seat cost Rs. 3,000 on one day but Rs. 9,000 on another day? Why do shops and malls announce discounts at certain times of the year? Have you ever wondered about the reasons behind these situations in a market?

In the Grade 7 chapter 'Understanding Markets', you learnt about the interaction among buyers and sellers and how prices adjust when the seller sets them too high or too low. Prices do not change randomly; they react to what people want, how much is available, the seasons, festivals, trends, and sometimes even rumours. Whether it is snacks, movie tickets, mobile phones, or vegetables, the prices of all goods and services are determined by two powerful forces constantly at work, that is, demand and supply.

This chapter explores the concepts of demand, supply, and price determination and provides a glimpse of the outcomes of their interplay in real - world situations.

9.1 Demand

As the mango season approaches, the prices of mangoes are generally high, so people tend to buy them in smaller quantities. But when prices start falling, people prefer to buy larger quantities. The quantity of a product that people are willing and able to buy at a particular price, depending on their needs, preferences, season, trend, and income, is called the demand for the product. Demand is not just the desire to buy something; it is the willingness complemented by the ability or purchasing power to buy it.

As with mangoes, when the price of any product rises, the quantity demanded decreases, and when the price falls, the quantity demanded increases. This phenomenon is called the Law of Demand, which highlights the inverse relationship between the price of a product or service and its quantity demanded.

[Figure 9.1: P = Price, Q = Quantity, See in your textbook]

Let us understand this with an example. At the beginning of the mango season, the price of mangoes was very high (Rs. 150 per kg). Srivalli, a consumer, bought only 1 kg. As more mangoes became available in the market, over time, the price fell to Rs. 100, so she bought 2 kg, and later, when the price dropped to Rs. 50 per kg, she bought 3 kg. The quantity of a good or service that an individual consumer wants to buy at different prices, keeping other factors constant, is known as individual demand. For Srivalli, the individual demand is shown in the table below, which is also known as the 'demand schedule'. This demand schedule, when represented graphically, is called the 'demand curve'.

[Figure 9.2: Individual demand schedule (a) and Individual demand curve (b), See in your textbook]

The y - axis in the Fig. 9.2 (b) represents the price of mangoes (in Rs.), and the x - axis shows the quantity demanded of mangoes (in kg). Srivalli bought 1 kg of mangoes at Rs. 150 (represented at point A). As the price fell to Rs. 100 per kg, she bought 2 kg (at point B). But as the price fell to Rs. 50, she bought 3 kg (at point C). When the points of intersection, such as A, B, and C, are connected, the downward sloping line DD' is called the demand curve. The downward - sloping individual demand curve represents the inverse relationship between price and the quantity of a product demanded by the buyer, assuming other factors like income, taste, etc., to be constant.

Teacher's Note

Remember that the Law of Demand shows why prices and quantities move in opposite directions. When the price is high, you buy less (like 1 kg at Rs. 150); when it is low, you buy more (like 3 kg at Rs. 50). This inverse relationship is the key idea to grasp.

What happens when others want to buy mangoes too? The total quantity of mangoes demanded by all potential buyers at different prices is known as market demand, that is, the sum of all individual demand. Let us consider two more consumers, Alex and Israt, whose individual demand is given in the schedule below:

By summing the demand of all three consumers, Q1 + Q2 + Q3, the market demand QD is derived. When the market demand is plotted at different prices, the downward - sloping market demand curve is obtained.

[Figure 9.3: Individual demand curve (a) and market demand curve (b), See in your textbook]

Teacher's Note

Market demand is just the sum of what each buyer wants at every price level. At Rs. 150, Srivalli buys 1 kg, Alex buys 2 kg, and Israt buys 3 kg, so the market demand is 6 kg. Do not confuse individual demand (one person's choice) with market demand (all buyers' combined choice).

Key Points

• Demand is not just wanting something; it means you are willing and able to buy it at a particular price with your purchasing power.
• The Law of Demand states that when price goes up, the quantity demanded goes down, and when price goes down, the quantity demanded goes up. This inverse relationship is shown by the downward - sloping demand curve.
• Individual demand is what one person wants to buy at different prices, while market demand is the total quantity all buyers in the market want to buy at each price level.

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