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NCERT Solutions for Class 9th Social Science Chapter 9 The chapter's opening paragraph — In-text Questions

Book page 195 Updated on2026-09-08

Q1.
What happens if the mangoes your parents bought last week are now half the price?
Answer

Your family will almost certainly buy more of them — and that is the Law of Demand in one sentence. The chapter's own example is exactly this: at ₹150 per kg Srivalli bought 1 kg, at ₹100 she bought 2 kg, and at ₹50 she bought 3 kg.

Last week: ₹150 per kg → bought 1 kg
This week: price halved to ₹75 per kg
Quantity demanded rises — the same money now buys more
On the graph: you slide down along the demand curve DD’

Two separate things are happening, and it is worth keeping them apart. Your family's demand has not changed — the whole schedule of what you would buy at each price is the same as last week. What changed is the price, so you have moved to a different point on that same schedule.

Why the price halved in the first place: almost always because supply rose. As the chapter says, “At the start of mango season, supply is low, making mangoes costly. Mid-season, the supply increases and prices fall.” More mangoes arriving in the market at a time when demand has not changed leaves sellers with unsold, perishable stock, and the price falls until the extra fruit is cleared.
Q2.
Why are vegetables expensive in the morning but are cheaper in the evening?
Answer

Because the seller's position changes completely between morning and evening, while the vegetables get less valuable by the hour. The same stock is worth more to a buyer in the morning and worth less to the seller by closing time, so the price falls through the day.

MorningEvening
DemandHigh — buyers want the freshest produce and are willing to pay for itLower — most households have already bought for the day
Supply positionThe seller has the whole day ahead and can wait for a good priceUnsold stock will wilt or rot overnight; waiting costs more than cutting the price
ResultPrice is held upPrice is cut to clear the stock
Why it happens: vegetables are perishable, so an unsold tomato at closing time is worth close to nothing. Any price above zero is better than throwing it away. The seller therefore keeps lowering the price until the remaining quantity is taken — which is precisely the surplus-clears-by-price-fall mechanism of the chapter, compressed into a single day.
Check it yourself: question 9(c) of the end-of-chapter set asks the same thing about tomatoes. The answer also explains why a shop selling non-perishable goods — steel vessels, notebooks — does not cut prices every evening.
Q3.
Or why does the price of onions seem to change every few months?
Answer

Because the demand for onions stays roughly steady all year while the supply arrives in bursts. A curve that barely moves and a curve that swings a great deal give an intersection point that keeps jumping.

The chapter names the forces at work in the ‘Other Determinants of Supply’ section and in the LET’S EXPLORE box on page 203:

  • Seasonality of the harvest. Fresh arrivals push market supply up and the price down; between harvests supply comes only from storage and the price rises.
  • Weather and disasters. Unseasonal rain or a failed crop cuts supply — “change in weather, disaster” is on the chapter's own list.
  • The farmer's earlier choice. If prices were poor last season, some farmers planted something else instead — the chapter's wheat-and-chickpea example in Fig. 9.6 — so this season's supply is smaller.
  • Expectations and hoarding. If wholesalers expect prices to rise, “they might hold back supply now to sell later at higher prices”, which raises the price today.
Why demand hardly helps: onions go into everyday cooking, so households buy nearly the same quantity whether the price is low or high. When buyers cannot easily cut back, a small fall in supply forces a large rise in price before the market clears — which is why onion prices make news in a way that, say, ice-cream prices do not.
Q4.
Why does the same flight seat cost ₹3,000 on one day but ₹9,000 on another day?
Answer

Because the supply of seats on that flight is fixed while the demand for them changes every day — so the whole adjustment has to come out of the price. This is the airline version of the hotel example on page 205, and the chapter's list of tariff factors transfers almost word for word.

Seats on the aircraft = fixed (supply cannot rise for tomorrow's flight)
Demand on a holiday / festival weekend = high → ₹9,000
Demand on an ordinary weekday = low → ₹3,000
Ratio = 9,000 ÷ 3,000 = 3 times

The chapter's own list of what such prices depend on fits exactly: how fast seats are getting booked, what nearby competitors are charging, festivals or conferences in the area, weather, the number of days left before travel, and past booking trends.

Why the airline does it: an empty seat earns nothing once the aircraft has taken off — the revenue from it is lost forever. So the airline raises the price when it can see the flight filling fast, and drops it when seats are going unsold, changing the price many times to earn the maximum revenue (the chapter's margin term: the total money earned from sales before expenses are deducted).
Q5.
Why do shops and malls announce discounts at certain times of the year?
Answer

Because a lower price sells a far larger quantity, and at particular times of the year that trade is worth making. A discount is a deliberate move down the demand curve, made when the seller values clearing stock more than the margin on each item.

The reasons cluster into three:

  • The season brings the buyers. The chapter's seasonality point — festive shopping, the start of an academic session, the change of weather — means many more people are in the market anyway. A discount at that moment converts a crowd into sales.
  • Old stock must go. End-of-season clothes and last year's phone model lose value once the new stock arrives. Selling at a reduced price is better than holding goods that will be worth still less.
  • Buyers are waiting for it. The chapter notes that “people delay buying durables before Diwali or the New Year, expecting festival discounts.” Once buyers expect a sale, present demand falls until the sale actually arrives — so shops must hold one.
Why the shop still gains: profit depends on price times quantity, not price alone. If a shirt priced at ₹1,000 sells 100 pieces, and at ₹600 it sells 400, the sales value goes from ₹1,00,000 to ₹2,40,000. Add the shelf space freed for new stock and the new customers who come for the sale and stay, and the discount can be the better decision — which is why it is announced, not forced.
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