9. The Price Puzzle: What Drives the
Market
|
The Big Questions 1.
What factors influence demand and supply of goods and services in a market? 2.
How are prices determined through demand-supply interaction? 3.
What is market equilibrium — does it really exist in the real world? 4.
How and why does the government intervene in the market? |
1. Introduction
Prices
of goods and services in a market do not change randomly. They respond to how
much people want a good (demand), how much is available (supply), the season,
festivals, trends, and even rumours. Whether it is mangoes, movie tickets,
mobile phones, or flight tickets, prices of everything are governed by two
constantly-working forces — Demand and Supply. This chapter explains these two
forces, how their interaction fixes the price (market equilibrium), whether
such equilibrium is stable in real life, and why and how the government
sometimes intervenes in markets.
2. Demand
Meaning: 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 demand. Demand is not merely
the desire to buy something — it is the willingness to buy backed by the
ability (purchasing power) to buy it.
2.1 Law of Demand
The
Law of Demand states that, other factors remaining constant, when the price of
a product rises, the quantity demanded falls; and when the price falls, the
quantity demanded rises. It shows an inverse (negative) relationship between
price and quantity demanded.
2.2 Individual Demand and the Demand Curve
The
quantity of a good that a single consumer wants to buy at different prices,
other factors held constant, is called individual demand. A table showing this
is called a demand schedule; when plotted on a graph it becomes a demand curve.
Example (Srivalli buying mangoes):
|
Price of mango per kg (₹) |
Quantity demanded by Srivalli (kg) |
|
150 |
1 |
|
100 |
2 |
|
50 |
3 |
On
the graph, price is on the Y-axis and quantity on the X-axis. Joining points A
(₹150,1kg), B (₹100,2kg) and C (₹50,3kg) gives a downward-sloping line DD′ —
the individual demand curve. It slopes downward because of the inverse
price–quantity relationship, assuming income, taste, etc. remain unchanged.
2.3 Market Demand
Market
demand is the total quantity of a good demanded by all buyers in the market at
different prices — i.e., the sum of individual demands of every consumer.
|
Price (₹) |
Srivalli (kg) |
Alex (kg) |
Israt (kg) |
Market Demand (kg) |
|
150 |
1 |
2 |
3 |
6 |
|
100 |
2 |
4 |
6 |
12 |
|
50 |
3 |
6 |
9 |
18 |
|
Key point (Don't Miss Out) The
market demand curve is FLATTER than an individual demand curve. Because
market demand aggregates many consumers, the same fall in price produces a
much larger total change in quantity (Srivalli's demand rises by only 2 kg
when price falls from ₹150 to ₹50, but market demand rises by 12 kg over the
same fall). |
2.4 Other Determinants of Demand (besides price)
• Price
of Related Goods:
◦ Substitute
goods — goods that can replace each other (e.g., tea and coffee). If the price
of one substitute rises, demand for the other (relatively cheaper) good
increases.
◦ Complementary
goods — goods used together (e.g., smartphones & earphones, cars & petrol,
movie tickets & popcorn). If demand for one rises/falls, demand for the
other moves in the same direction, even if its own price is unchanged.
• Income
of the consumer: A rise in income lets consumers buy more or shift to
higher-quality products, raising demand even when prices stay the same.
• Taste
and preference: Personal likes/dislikes determine demand independent of price
(e.g., Srivalli prefers mangoes over cheaper oranges). Population size and
composition (more children, working adults, or elderly) also shape demand for
different products.
• Diminishing
Marginal Utility: The additional satisfaction (utility) from each successive
unit of a good consumed keeps falling. As utility falls, willingness to pay
falls, so demand for further units falls.
• Seasonality:
Demand for many goods changes with weather, festivals, and cultural habits
(e.g., sweets during festivals, sweaters in winter, notebooks at the start of
the academic session) — independent of price.
• Future
price expectations: If consumers expect prices to fall, they postpone purchases
(demand falls now); if they expect prices to rise, they buy immediately (demand
rises now). E.g., people delay buying durables before Diwali expecting festival
discounts.
3. Supply
Meaning: Supply is the quantity of a product
that sellers are willing and able to offer for sale at a particular price.
3.1 Law of Supply
As
price increases, quantity supplied increases; as price decreases, quantity
supplied falls. This is a direct (positive) relationship, because higher prices
raise profitability, encouraging existing producers to produce more and
attracting new firms into the market.
3.2 Individual Supply and Market Supply
Individual
supply is the quantity a particular seller offers at different prices. Market
supply is the sum of individual supplies of all sellers in the market.
|
Price (₹) |
Seller A (kg) |
Seller B (kg) |
Seller C (kg) |
Market Supply (kg) |
|
50 |
1 |
3 |
2 |
6 |
|
100 |
2 |
4 |
6 |
12 |
|
150 |
3 |
7 |
8 |
18 |
Plotting
price against quantity gives an upward-sloping supply curve (SS′ for an
individual seller, SmSm′ for the market).
3.3 Other Determinants of Supply
• Price
of related goods: A producer may shift resources toward whichever good is more
profitable (e.g., a farmer grows more chickpeas instead of wheat if chickpea
prices are higher).
• Number
of sellers in the market: More sellers (higher competition) raises market
supply, which tends to lower price; fewer sellers lowers supply, raising price.
• Technology:
Better technology lowers the cost of production, allowing producers to supply
more at the same price (e.g., drip irrigation, weather sensors, cold storage for
mangoes).
• Future
expectations: If producers expect demand/prices to rise later, they may hold
back present supply to sell later at a higher price, and vice versa (e.g.,
potato wholesalers holding stock before the peak season).
4. Market Equilibrium
Meaning: Market equilibrium is the point where
quantity demanded equals quantity supplied (Qd = Qs). At this point there is no
shortage (excess demand) and no surplus (excess supply), and there is no
pressure on price to change — the market is said to be 'cleared'.
|
Price (₹) |
Qty Demanded (kg) |
Qty Supplied (kg) |
Comparison |
Outcome |
|
40 |
38 |
6 |
Qs
< Qd |
Excess
Demand |
|
100 |
12 |
12 |
Qs
= Qd |
Market
Equilibrium |
|
150 |
8 |
43 |
Qs
> Qd |
Excess
Supply |
Equilibrium
price = ₹100, Equilibrium quantity = 12 kg. Graphically, equilibrium (point E)
is where the demand curve (DmDm′) intersects the supply curve (SmSm′).
• At
a price below equilibrium: Quantity demanded > quantity supplied →
Excess demand / shortage → price tends to rise.
• At
a price above equilibrium: Quantity supplied > quantity demanded →
Excess supply / surplus → price tends to fall.
4.1 Does Market Equilibrium Exist in the Real World?
In
theory, equilibrium is a fixed intersection point. In reality, markets are
dynamic — constantly changing due to technology, wages, interest rates, wars,
political events, pandemics, weather, and natural disasters. So the market is
always adjusting toward a new equilibrium and never permanently settles at one
point. Example: During COVID-19, sudden surge in demand for face masks (supply
couldn't catch up) pushed prices up sharply; as supply adjusted, prices fell
back over time.
Example
— Hotel tariffs: A Goa hotel may charge ₹1,500 (off-season weekday), ₹8,000
(weekend in tourist season), and ₹25,000 (New Year's Eve) for the same room,
depending on booking speed, competitors' tariffs, festivals/events, weather
forecasts, days left before arrival, and past booking trends — showing how real
markets constantly re-adjust prices to changing demand and supply.
5. Role of Government in the Economy
India
is a market-based, regulated economy where prices generally depend on demand
and supply. But markets do not always work fairly — they allocate goods based
on willingness and ability to pay, which can leave essential goods unaffordable
for some. Hence the government intervenes in three key ways:
5.1 Regulation of Unfair Practices
• Price
Ceiling: A government-imposed MAXIMUM price for a good/service, to prevent
overcharging on essential goods (e.g., capping the price of essential medicines
or sanitisers during COVID-19 under the Essential Commodities Act, 1955).
• Price
Floor: A government-imposed MINIMUM price/wage, to protect sellers/workers
(e.g., minimum wages for workers). To be effective, a price floor must be set
ABOVE the market equilibrium price.
• Curbing
Monopoly: A monopoly (single/few sellers controlling the entire supply of a
good with no close substitute) can charge high prices, offer poor quality, and
restrict supply. The government regulates such practices through regulators
such as RBI (banking), Central Consumer Protection Authority (unfair trade
practices), TRAI (telecom), and SEBI (securities market).
5.2 Provision of Public Goods
Public
goods (roads, bridges, parks, streetlighting, national defence, sanitation,
drainage) benefit all citizens but are not provided by private companies since
they don't generate direct profit. Because individuals tend to think 'others
will pay, I'll use it free' (the free-rider problem), such goods are
under-funded if left to private/voluntary contribution — so the government must
provide or fund them for social welfare, economic development, and equal
access.
5.3 Limitations of Government Intervention
• Price
distortions & reduced producer incentives: Prices fixed below market levels
discourage producers (e.g., a wheat price cap below the market price reduces
farmers' earnings, leading to lower production and shortages).
• Compliance
burdens: Excess regulations, licenses, and permits raise costs, hurting small
businesses and the 'ease of doing business'.
• Discourages
innovation & entrepreneurship: Heavy regulation/price controls reduce the
incentive to invest in better technology, seeds, or irrigation, since returns
are capped, reducing long-run productivity.
6. Key Terms (Glossary)
|
Term |
Meaning |
|
Purchasing
power |
A
measure of how much one unit of currency can buy at a particular time. |
|
Related
goods |
Goods
whose demand is interconnected — substitutes or complements. |
|
Market
equilibrium |
The
point where quantity supplied equals quantity demanded; no surplus or
shortage. |
|
Revenue |
Total
money a business earns from sale of goods/services before expenses are
deducted. |
|
Price
ceiling |
An
imposed maximum price a seller can charge for a good/service. |
|
Price
floor |
An
imposed minimum price/wage; must be set above equilibrium price to be
effective. |
|
Monopoly |
A
market with a single seller controlling the entire supply of a good, with no
close substitutes. |
|
Hoarding |
Accumulating
goods beyond immediate need, fearing future shortages/price rise. |
|
Black
marketing |
Illegal
trade of goods/services that are banned or price-regulated. |
|
Ease
of doing business |
How
simple it is to start, run, and close a business — depends on regulations,
bureaucracy, legal framework. |
7. Quick Revision Summary
• Demand:
quantity consumers are willing & able to buy at a price. Law of Demand →
inverse price-quantity relation. Determinants: related goods' prices, income,
tastes, seasonality, future expectations, population.
• Supply:
quantity sellers are willing & able to offer at a price. Law of Supply →
direct price-quantity relation. Determinants: related goods' prices, number of
sellers, technology, input costs, future expectations.
• Market
Equilibrium: Qd = Qs; price where market clears. Real markets constantly move
toward new equilibria as conditions (weather, trends, technology, income)
change — a truly 'static' equilibrium rarely persists.
• Government
intervenes to correct market failure (unaffordable essentials, monopoly,
under-provided public goods) via price ceilings/floors and regulation, but
excessive intervention can distort incentives, raise compliance costs, and
discourage innovation.
8. Solved Exercise Answers (Questions and
Activities)
Q1. "An increase in income always leads to a rise
in demand for goods." Defend or refute.
Refuted.
An increase in income does not always raise demand for ALL goods. It depends on
the type of good:
• For
normal goods (e.g., branded clothes, better food, electronics), demand rises as
income rises, since consumers can now afford more or higher-quality products.
• For
inferior goods (e.g., cheaper cereals, second-hand goods, low-cost local
transport), demand may actually FALL as income rises, because consumers switch
to better substitutes once they can afford them.
Hence,
the statement is only partly true — it holds for normal goods but not for
inferior goods.
Q2. If petrol prices double, what happens to:
• (a)
Demand for diesel cars: Increases — diesel becomes a relatively cheaper
substitute fuel, so buyers shift towards diesel vehicles.
• (b)
Demand for electric cars: Increases — EVs (which don't use petrol) become a
more attractive substitute, so their demand rises.
• (c)
Demand for car accessories: Likely falls (or grows slower) — since car
accessories are complementary to (petrol) car usage; higher running cost may
reduce car purchases/usage, reducing demand for accessories.
• (d)
Demand for public transport: Increases — public transport becomes a relatively
cheaper substitute for using a personal petrol vehicle.
Q3. A farmer replaces manual irrigation with drip
irrigation (reduces water use 40%, increases yield 30%). Effect on:
• (a)
Cost of production: Falls — less water (and associated labour/energy) is used
per unit of output, and yield rises, so average cost of production decreases.
• (b)
Willingness to supply at different prices: Increases — since production is now
cheaper and more profitable at every price level, the farmer is willing to
supply a larger quantity at each price; his individual supply curve shifts to
the right (outward).
• (c)
Overall market supply (if many farmers adopt it): The market supply curve
shifts rightward/outward — at every price, the total quantity supplied in the
market increases, which (other things equal) tends to lower the equilibrium
price and raise the equilibrium quantity.
Q4. During online festival sales, prices are very low.
Explain using demand and supply.
Sellers
deliberately lower prices during festival sales to boost the quantity demanded
sharply (Law of Demand: lower price →
higher quantity demanded). Sellers are willing to sell at a lower margin per
unit because they expect to gain from a much higher volume of sales, clear
excess inventory, attract new customers, and compete with rival
platforms/sellers.
Effect
on equilibrium: When prices are lowered below the earlier equilibrium price,
quantity demanded exceeds quantity supplied at the old equilibrium, so sellers
increase supply/stock to meet the surge; a new, temporary equilibrium is
reached at a lower price and a much higher quantity.
Who
benefits: Both. Consumers benefit from lower prices and more choice; sellers
can benefit too — through higher total revenue (from larger sales volume),
clearing old stock, building customer loyalty, and higher future sales — even
though profit margin per unit is lower.
Q5. Government sets a maximum sale price for an
essential vaccine below the market-driven price. What is likely?
Answer: (b) Shortage.
Explanation:
A price ceiling set below the equilibrium price means the fixed price is lower
than what the market would otherwise charge. At this lower price, quantity
demanded (which rises as price falls) will exceed quantity supplied (producers
are less willing to supply at a lower, less profitable price). This gap between
higher quantity demanded and lower quantity supplied is called excess demand or
a shortage.
Q6. Other goods with price controls, and reasons
(sample answer)
• Essential
medicines: Prices capped under the Drug Price Control Order, to keep
life-saving medicines affordable for all.
• LPG
cylinders / kerosene: Subsidised/controlled prices to make cooking fuel
affordable for low-income households.
• Foodgrains
under the Public Distribution System (PDS): Sold at a fixed, subsidised price
to ensure food security for the poor.
• Electricity
tariffs: Regulated by state electricity regulatory commissions to prevent
overcharging of consumers, especially in agriculture and low-income households.
(Note:
Students may also mention minimum support price for crops (a price floor for
farmers), or minimum wages for workers.)
Q7. Can excessive government regulation hurt markets?
Explain with examples.
Yes.
While some regulation is necessary to correct market failures, EXCESSIVE
regulation can be harmful:
• Price
distortions: If prices are fixed below the market level (e.g., wheat capped at
₹20/kg when the market price is ₹30/kg), farmers earn less than they would
otherwise, discouraging production and causing shortages.
• Compliance
burden: Too many licenses/permits (e.g., a small restaurant needing multiple
clearances for food safety, fire safety, pollution control) raise costs and
time for entrepreneurs, hurting the ease of doing business.
• Discourages
innovation: When returns are capped by price controls, producers have little
incentive to invest in better technology, seeds, or irrigation, reducing
long-term productivity and output.
Q8–Q9. Activity-based questions (guidance for students)
Q8
asks students to record how much guava they (and three friends) would buy at
₹100, ₹80, ₹50 and ₹20 per kg, then plot individual and combined (market)
demand curves. Expected pattern: quantity demanded should rise as price falls
(Law of Demand), and the combined/market demand curve should be flatter than
any individual's curve (as seen in the mango example in the chapter).
Q9
asks students to visit a local vegetable market and observe: (a) prices are
usually set through negotiation/bargaining between buyers and sellers,
influenced by supply from wholesalers/mandis; (b) prices of some vegetables are
very high or low due to changes in supply (weather, transport, season) relative
to demand; (c) tomato prices are often high in the morning (fresh stock, higher
initial demand) and fall by evening as sellers try to clear perishable stock
before closing (excess supply relative to remaining demand near closing time).
Q10. Classify as substitute or complementary goods
|
Goods |
Type |
|
(a)
Movie ticket & popcorn |
Complementary |
|
(b)
Eraser & pencil |
Complementary |
|
(c)
Laptop & computer (desktop) |
Substitute |
|
(d)
Air Conditioner & cooler |
Substitute |
|
(e)
Notebook & pen |
Complementary |
|
(f)
Apple & banana |
Substitute |
|
(g)
Mobile & earphones |
Complementary |
Q11. Based on Fig. 9.8 (Demand curve DD′, Supply curve
SS′)
• (a)
Point E represents the market equilibrium — the point where the demand curve
intersects the supply curve, i.e., quantity demanded = quantity supplied.
• (b)
Equilibrium price = ₹250; Equilibrium quantity = 30 kg (as read from the graph,
at point E).
• (c)
At the upper dashed price line (₹300): Point A (on DD′) shows the lower
quantity demanded (~23 kg) at that price, while point B (on SS′) shows a higher
quantity supplied (~37 kg). Since quantity supplied (B) exceeds quantity
demanded (A) at ₹300, the gap A–B represents excess supply (a surplus). This
surplus will push the price back down towards equilibrium.
• (d)
At the lower dashed price line (₹160): Point F (on DD′) shows a higher quantity
demanded (~43 kg), while point C (on SS′) shows a lower quantity supplied (~17
kg). Since quantity demanded (F) exceeds quantity supplied (C) at ₹160, the gap
C–F represents excess demand (a shortage). This shortage will push the price
back up towards equilibrium.
• (e)
If the price stays fixed at the lower dashed line, the shortage (excess demand)
will persist. In a free market, buyers competing for the limited quantity
available would bid the price up, and/or sellers — seeing strong demand — would
raise the price, pushing the market back up towards the equilibrium price of
₹250.
Q12. Draw the market equilibrium graph for the given
demand schedule
|
Price (₹) |
10 |
20 |
30 |
40 |
50 |
|
Qd
(kg) |
5 |
10 |
15 |
20 |
25 |
|
Qs
(kg) |
25 |
20 |
15 |
10 |
5 |
• (a)
Plot: Mark Price on the Y-axis and Quantity on the X-axis. Plot the Qd points
(5,10,15,20,25 kg at prices 10,20,30,40,50) and join them — this gives a
downward-sloping demand curve. Plot the Qs points (25,20,15,10,5 kg at the same
prices) and join them — this gives an upward-sloping supply curve. The two
curves cross at one point.
• (b)
Equilibrium: The two curves intersect where Qd = Qs = 15 kg, at Price = ₹30.
So, Equilibrium Price = ₹30, Equilibrium Quantity = 15 kg.
• (c)
At ₹20: Qd = 10 kg, Qs = 20 kg → Qs > Qd →
Excess Supply of 10 kg (a surplus). Since sellers cannot sell all they have
produced, the price will tend to fall towards ₹30.
• At ₹40: Qd = 20 kg, Qs = 10 kg →
Qd > Qs → Excess Demand of 10 kg (a shortage). Since
buyers cannot get all they want, the price will tend to rise towards ₹30.
|
Exam Tip Always
remember: Law of Demand = inverse relation (price↑
→ Qd↓);
Law of Supply = direct relation (price↑
→ Qs↑).
Market equilibrium is where Qd = Qs. Below equilibrium price →
shortage (price rises); above equilibrium price →
surplus (price falls). A price floor works only if set ABOVE equilibrium; a
price ceiling works only if set BELOW equilibrium. |