In the NCERT diagram that derives a demand curve, panel (a) shows the consumer’s optimum on an indifference curve at the price P′1 of bananas, where she buys X′1. When the price falls to P1, she buys X1 at a new optimum. In panel (b), P′1 is plotted against X′1 and P1 against X1. What do these points lie on?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → The consumer’s demand curve for bananas
Each point pairs a price of bananas with the quantity she buys at that price. A curve through such points is her demand curve for bananas.
Option (1) The consumer’s indifference curve — Incorrect. An indifference curve plots bundles of two goods that give equal satisfaction.
Option (2) The consumer’s demand curve for bananas — Correct. Price against quantity of one consumer is her demand curve.
Option (3) The consumer’s budget line — Incorrect. The budget line plots bundles of two goods that cost her whole income.
Option (4) The market demand curve for bananas — Incorrect. Market demand adds the demands of all consumers; here there is one.
NCERT (2026-27): “2.4.2 Deriving a Demand Curve from Indifference Curves and Budget Constraints … In panel (b) of figure 2.14, we plot P'1 against X'1 which is the first point on the demand curve for X1. … Thus, demand for bananas increases as its price drops. We plot P1 against X1 in panel (b) of figure 2.14 to get the second point on the demand curve for X1. … The demand curve for bananas is thus negatively sloped. …” |