NCERT Solutions for Class 9th Social Science Chapter 9 Demand — DON'T MISS OUT
Book page 198 Updated on2026-09-19
Q1.
Did you notice that the market demand curve is flatter than Srivalli's individual demand curve? Why is that?
The two curves the question compares, redrawn from the book: Srivalli’s individual demand curve DD’ (Fig. 9.2 (b), page 196 — A at 1 kg/₹150, B at 2 kg/₹100, C at 3 kg/₹50) and the market demand curve DmDm’ (Fig. 9.3 (b), page 197 — 6 kg, 12 kg and 18 kg at the same three prices). The two panels use different quantity scales, exactly as the book prints them.
Answer
Because the same fall in price is answered by one buyer in Srivalli's curve and by three buyers in the market curve — so the market curve has to stretch six times as far sideways for the same drop downwards. The chapter's own numbers make it exact.
Price falls ₹150 → ₹50, a fall of ₹100 in both cases
Srivalli's quantity: 1 kg → 3 kg, a rise of 2 kg
Market quantity: 6 kg → 18 kg, a rise of 12 kg
Steepness of Srivalli's curve = ₹100 ÷ 2 kg = ₹50 per extra kg
Steepness of the market curve = ₹100 ÷ 12 kg = ₹8.33 per extra kg
A curve that needs only ₹8.33 of price fall to sell one more kilogram lies much closer to the horizontal than one that needs ₹50. That is what ‘flatter’ means.
Both curves are drawn on the same scale from Tables 9.1. The same ₹100 fall in price buys 2 extra kilograms from Srivalli but 12 extra kilograms from the whole market, so the market line leans far closer to the horizontal.
Why it happens: market demand “aggregates many consumers, so the same price change creates a larger total quantity response.” Every buyer adds their own reaction to the price fall — Srivalli's +2 kg, Alex's +4 kg and Israt's +6 kg add to +12 kg — and the more buyers there are, the further right the curve reaches for each rupee the price drops.
Tip: ‘flatter’ is a statement about the slope, not about the position. The market curve is not a different kind of curve — it slopes downward for exactly the same reason. It is simply the horizontal sum of the individual curves, so it is longer sideways at every price.