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Class 9 Economics: The Price Puzzle, demand, supply and market price, 8 practice questions with answers

CMDLearn · 3 November 2026

These are 8 practice questions on Chapter 9 of the new NCERT Class 9 Social Science textbook, Understanding Society: India and Beyond (Part 1, first published June 2026), "The Price Puzzle: What Drives the Market". It comes straight after the first Economics chapter, on the problem of choice, and is the second Economics chapter of Part 1. Each question has a worked answer and the textbook page it rests on. They follow the chapter: adding up a market demand schedule, what else moves demand, substitutes and complements, adding up market supply, what else moves supply, finding the equilibrium price, price ceilings and floors, and the government's part in a market.

These questions are our own, drafted with AI help. Every number was re-computed by a script and every answer was checked against the chapter, but no practising teacher has reviewed them yet. None of them is a textbook question reworded. If you find a mistake, please tell us.

How this chapter is examined

This is a new book for 2026-27. CBSE's Class IX Social Science curriculum gives this chapter 8 teaching hours. It lists the laws of demand and supply, how real markets differ from the textbook model (necessities, luxury goods, perishable items and expectations), price ceilings, and market failures, naming externalities, information asymmetry and public goods (curriculum, PDF page 11). The chapter itself explains public goods and monopoly but does not define externalities or information asymmetry, so ask your teacher how much is expected on those. CBSE says the marks for each unit "will be provided shortly" (PDF page 14), so check with your school how the annual exam is split.

What the chapter says you need

Facts from the NCERT textbook (Understanding Society: India and Beyond, Class 9 Part 1, Chapter 9, printed pages 195 to 213), in our words:

• Demand (page 196): the amount of a good people are willing and also able to buy at a given price. Wanting something is not enough; you need the money to pay for it.
• Law of Demand (pages 196-197): when the price goes up, people buy less, and when it goes down, they buy more, other things such as income and taste staying the same. The demand curve therefore slopes downwards.
• Individual and market demand (pages 196-198): one buyer's quantities at each price form an individual demand schedule; adding every buyer's quantity at each price gives the market demand. The market curve is flatter, because a price change moves many buyers at once.
• Other things that move demand (pages 198-200): prices of related goods (substitutes, which can replace each other, and complements, which are used together), the buyer's income, tastes and preferences, the size and make-up of the population, the season, and what buyers expect prices to do next. Each extra unit of a good gives less satisfaction than the one before (diminishing marginal utility), so the willingness to pay for more falls.
• Supply and the Law of Supply (pages 200-201): how much sellers are ready, and able, to put on sale at a given price. A higher price means more profit, so sellers offer more and new firms join; the supply curve slopes upwards. Market supply is the sum of every seller's supply.
• Other things that move supply (pages 202-203): the prices of other goods the seller could make instead, the number of sellers, technology, and what producers expect demand and prices to do.
• Market equilibrium (pages 203-204): the price at which the quantity buyers want equals the quantity sellers offer. Below it there is excess demand (a shortage); above it, excess supply (a surplus). On a graph it is where the two curves cross.
• Real markets (pages 204-205): demand and supply keep shifting with technology, wages, interest rates, wars, pandemics, weather and more, so the equilibrium keeps moving. Face masks in 2020 and hotel room tariffs are the book's examples.
• The government's part (pages 206-207): India is a market-based, regulated economy. The government can set a maximum price (a price ceiling) on essentials such as medicines and a minimum (a price floor) such as a minimum wage; a floor only works if it is set above the equilibrium price. It checks monopolies, where one seller controls supply, and regulators such as RBI, TRAI, SEBI and the Central Consumer Protection Authority keep markets transparent. It provides public goods such as roads, parks, street lighting, defence and drainage, which private firms rarely supply because they bring no direct profit.
• Limits of intervention (page 208): prices fixed below the market level can cut supply and cause shortages; heavy rules and permits burden small businesses; and price controls can weaken the reason to invest in better methods.

Demand

Question 1. Three students buy samosas from a school canteen. The number each would buy in a week at three prices is (made-up figures):

(a) Write the market demand at each price. (b) Which law does each row of numbers follow, and what shape will the demand curve have? (c) When the price falls from ₹20 to ₹10, by how much does Priya's demand rise, and by how much does market demand rise? Which of the two curves will be flatter?

Answer: (a) 3 samosas at ₹20, 7 at ₹15 and 13 at ₹10; (b) the Law of Demand, so the curve slopes downwards; (c) Priya buys 3 more, the market 10 more, so the market curve is flatter. (a) Market demand is the sum of every buyer's demand at each price (page 197): 1 + 2 + 0 = 3, 2 + 4 + 1 = 7 and 4 + 6 + 3 = 13. (b) For every student, a lower price means a larger quantity, which is the inverse link between price and quantity demanded that the chapter calls the Law of Demand, shown by a downward-sloping curve (pages 196-197). (c) Priya goes from 1 to 4 (a rise of 3); the market goes from 3 to 13 (a rise of 10). Because the same fall in price brings a bigger change in total quantity, the market curve is flatter (page 198).

Question 2. In each case the price of the good has not changed. Say which factor in the chapter is at work, and whether the demand it describes goes up or down: (a) a family's monthly income rises and they start buying more fruit; (b) shops sell far more raincoats just before the monsoon; (c) people hear that television prices will drop in a sale next month, so they wait; (d) a town has many more elderly residents than ten years ago, and more walking sticks are sold there; (e) Ravi enjoys his third ice cream much less than his first and is not willing to pay as much for a fourth; (f) Arun loves idli and will not switch to bread even though bread is cheaper.

Answer: (a) income, up; (b) season, up; (c) future price expectations, down now; (d) make-up of the population, up; (e) diminishing marginal utility, down; (f) taste and preference, Arun's demand for idli stays up. (a) A higher income lets households buy more at the same prices (page 199). (b) Demand for some goods depends on the time of year and the weather (page 199). (c) If buyers expect prices to fall, they put off buying, so demand today falls (page 200). (d) The make-up of the population decides which goods are wanted, and more older people raise the demand for goods they need (page 199). (e) Each extra unit gives less satisfaction, so the willingness to pay, and with it demand, falls (page 199). (f) A buyer's tastes can keep demand for a good even when a cheaper one is on offer (page 199).

Question 3. Sort these pairs into substitute goods and complementary goods: (a) a cricket bat and a cricket ball; (b) a bus ride and a metro ride on the same route; (c) a gas stove and an LPG cylinder; (d) jaggery and sugar; (e) a fountain pen and a bottle of ink. Then answer: (f) if metro fares go up while bus fares stay the same, what is likely to happen to the demand for bus rides? (g) if the price of LPG cylinders rises sharply, what may happen to the demand for gas stoves?

Answer: substitutes: (b) and (d); complements: (a), (c) and (e). (f) Demand for bus rides is likely to rise. (g) Demand for gas stoves may fall. Substitutes can take each other's place, and complements are used together to give the buyer satisfaction (page 198). (f) When the price of one good goes up, people move to a cheaper alternative, so a rise in the price of a substitute raises demand for the other good (page 198). (g) With complements, a change in one affects the other: just as dearer cinema tickets can mean less popcorn sold in the hall (page 198), a much dearer cylinder makes cooking on gas costlier, so fewer people may buy a new gas stove.

Supply

Question 4. Three sellers bring marigold flowers to a temple market. The kilograms each would offer at three prices are (made-up figures):

(a) Work out the market supply at each price. (b) Which way does the market supply curve slope, and what law does it show? (c) Give the two reasons the chapter offers for sellers offering more at a higher price.

Answer: (a) 7 kg at ₹30, 12 kg at ₹60 and 20 kg at ₹90; (b) upwards, the Law of Supply; (c) higher profit for existing sellers, and new sellers joining. (a) Market supply is the sum of all the sellers' supply (page 201): 2 + 1 + 4 = 7, 4 + 3 + 5 = 12 and 6 + 5 + 9 = 20. (b) A higher price brings a larger quantity supplied, a direct relationship that gives an upward-sloping curve (pages 200-201). (c) A higher price makes producing more profitable, which pushes existing producers to raise output and draws new firms into the market (page 200).

Question 5. Which factor in the chapter changes supply in each case, and does supply rise or fall? (a) A new machine lets a tailor stitch a shirt in half the time. (b) The price of groundnut rises sharply while the price of cotton stays low, and a cotton farmer is choosing what to sow next season. (c) Six new bakeries open in a small town. (d) Onion traders expect the price to jump next month, so they hold back their stock. (e) A cyclone destroys most of a district's banana crop.

Answer: (a) technology, rises; (b) price of a related good, cotton supply falls (groundnut supply rises); (c) number of sellers, rises; (d) future expectations, supply now falls; (e) weather, falls. (a) Better technology lowers the cost of production, so producers can offer more (page 202). (b) The supply of one good depends on how profitable the other choices are, so a farmer moves land to the crop that pays more (page 202). (c) More sellers add to market supply, and if supply runs ahead of demand, prices fall (page 202). (d) Producers who expect higher prices later may hold goods back now to sell later (page 203). (e) The chapter's summary lists weather among the other factors that supply depends on (page 209), and a crop that is destroyed cannot be sold.

Equilibrium and the government

Question 6. In the week before a kite festival, a town's kite market has this schedule (made-up figures):

(a) What are the equilibrium price and quantity? (b) At ₹25, is there excess demand or excess supply, and how large is it? (c) At ₹45, is there excess demand or excess supply, and how large is it? (d) Starting from ₹25, which way would the price tend to move, and why?

Answer: (a) ₹35 and 50 kites; (b) excess demand (a shortage) of 40 kites; (c) excess supply (a surplus) of 45 kites; (d) up, towards ₹35. (a) Equilibrium is the price at which quantity demanded equals quantity supplied (page 203), and only at ₹35 are both 50. (b) At ₹25, buyers want 70 and sellers offer 30: 70 − 30 = 40 kites short. Below the equilibrium price there is excess demand (page 203). (c) At ₹45, sellers offer 75 and buyers want 30: 75 − 30 = 45 kites left over, which is excess supply (page 203). (d) A shortage pushes the price up (page 201), so the price moves up until the shortage is gone. At ₹35 the market is cleared, with no shortage or surplus (page 203).

Question 7. (a) Tur dal sells for ₹120 a kg in the open market. The government says no one may charge more than ₹90 a kg. Is this a price ceiling or a price floor? (b) Suppose at ₹90 buyers in a town want 1,000 kg a week but traders offer only 700 kg. How large is the gap, and what two problems might follow? (c) Separately, the government sets a minimum price of ₹30 a litre for milk, but milk already sells at ₹40. Will this rule change the market price? (d) Why does the chapter say a government may still cap the price of an essential good?

Answer: (a) a price ceiling; (b) a shortage of 300 kg, and the risk of hoarding and black-marketing (and, over time, less supply); (c) no, because a floor works only above the equilibrium price; (d) so that essentials stay within reach of poorer families. (a) A ceiling is a maximum price a seller may charge, and the chapter names essential goods such as medicines as the kind it is used for (page 206); here dal is held below its ₹120 market price. (b) 1,000 − 700 = 300 kg short. When a price is held below the market level, producers may lose the reason to supply and shortages follow (page 208), and the chapter's sanitiser story shows that shortages can bring hoarding and black-marketing (page 207). (c) A price floor has to be set above the equilibrium price to be effective (page 206); ₹30 is below the ₹40 market price, so sellers keep charging ₹40. (d) Markets share out goods by who is willing and able to pay, so the government acts for fairness, especially for vulnerable and low-income groups (page 206).

Question 8. For each pair, choose: (A) both true, and R explains A; (B) both true, but R does not explain A; (C) A true, R false; (D) A false, R true.

• Pair 1. Assertion: In real life, a market seldom stays at the same equilibrium for long. Reason: Things such as weather, technology, wages and pandemics keep changing demand and supply.
• Pair 2. Assertion: Street lights are mostly provided by private companies. Reason: Goods such as street lights do not usually bring the provider a direct profit.
• Pair 3. Assertion: A monopoly may charge more and offer less than a competitive market would. Reason: A monopolist's product has many close substitutes.
• Pair 4. Assertion: By size, India ranks fourth among the world's economies. Reason: India is a market-based economy with regulation.

Answer: Pair 1 (A); Pair 2 (D); Pair 3 (C); Pair 4 (B). Pair 1: the chapter says real markets keep adjusting to a new equilibrium because these conditions keep changing (page 204), so R explains A. Pair 2: public goods such as street lighting are usually provided by the government, because private firms see no direct profit in them (page 207), so A is false and R is true. Pair 3: one or a few sellers can charge more and supply less (page 206), so A is true, but a monopoly faces no close substitutes (page 206), so R is false. Pair 4: the chapter states both (page 206), but the kind of economy India runs does not explain its size ranking.

Practise more, and check your marks

• Another new Class 9 Social Science chapter on this site: Class 9 Social Science: Democracy, practice questions.
• Where these ideas lead in Class 10 Economics: Class 10 Economics: Development and Sectors of the Indian Economy.
• For a schedule question, show the sum or the gap at each price, as in Questions 1, 4 and 6, then name the law or the outcome. Draw the curves with price on the y-axis and quantity on the x-axis, as the book does (page 197).
• Using an AI to check your answers: how to use ChatGPT for homework without cheating yourself. This is a new book, and an AI may answer from an older Economics book, so check its answer against your textbook page.

Where CMDLearn fits

CMDLearn is building an AI tutor for Classes 1 to 10 that explains a step and checks the child's working, but leaves the writing to the child. It is still in development, and no child uses it yet. If you would like to hear when there is something to try, you can join the waitlist.

Sources

All opened and read on 3 November 2026. Page numbers are the printed page numbers of the textbook; printed page = PDF page + 194.

• NCERT, Understanding Society: India and Beyond, Class 9 Part 1 (first edition, June 2026), Chapter 9 "The Price Puzzle: What Drives the Market", printed pages 195-213 (demand and the Law of Demand, pages 196-198; other determinants of demand, pages 198-200; supply, pages 200-203; market equilibrium, pages 203-205; the role of government and its limits, pages 206-208; summary, page 209; questions and activities, pages 210-213): ncert.nic.in/textbook/pdf/iest109.pdf
• NCERT, the same book's opening pages (first edition June 2026; contents, Chapter 9 at page 195): ncert.nic.in/textbook/pdf/iest1ps.pdf
• CBSE, Social Science curriculum, Class IX, 2026-27 (Chapter 9 hours, contents and learning outcomes, PDF page 11; the note on the course structure, PDF page 14): cbseacademic.nic.in/web_material/CurriculumMain27/SecPart1/SocialScience_SecP1IX_2026-27.pdf

The facts are from the textbook pages above. The questions, the made-up schedules and the worked answers are our own, and every number was re-computed by script. This guide is general information; follow your teacher and the official CBSE notices.

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