An increase in the price of commodity X is likely to decrease the demand for commodity Y and a decrease in the price of commodity X is likely to increase the demand for commodity Y. How are X and Y related?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → X and Y are Complementary goods.
Some goods are used together — tea and sugar, shoes and socks, pen and ink. When tea becomes dearer, people drink less tea and so buy less sugar too. Such goods are complementary goods: the demand for one moves opposite to the price of the other, just as a rise in the price of X decreases the demand for Y.
Why the other options are incorrect
Option (2) X and Y are substitute goods. — Incorrect. Substitutes, such as tea and coffee, are used in place of each other. A rise in the price of one raises the demand for the other, the opposite of the relation between X and Y.
Option (3) X and Y are normal goods. — Incorrect. Normal goods are defined by how demand responds to the consumer’s income (it rises with income), not to the price of another good.
Option (4) X and Y are inferior goods. — Incorrect. Inferior goods too are defined by the response to income (demand falls as income rises); the term says nothing about how two goods are related in use.
Note: A same/similar question was asked in CUET (UG) in the papers below.
| 2026 | 2025 | 2024 | 2023 | 2022 |
| 19-05 S2 | 27-05 S2* | – | – | – |
* A similar question.
NCERT (2025-26): “2.4.4 Substitutes and Complements We can also study the relation between the quantity of a good that a consumer chooses and the price of a related good. The quantity of a good that the consumer chooses can increase or decrease with the rise in the price of a related good depending on whether the two goods are substitutes or complementary to each other. Goods which are consumed together are called complementary goods. Examples of goods which are complement to each other include tea and sugar, shoes and socks, pen and ink, etc. Since tea and sugar are used together, an increase in the price of sugar is likely to decrease the demand for tea and a decrease in the price of sugar is likely to increase the demand for tea. Similar is the case with other complements. In general, the demand for a good moves in the opposite direction of the price of its complementary goods.…” |