📘 Q.3 IAS Prelims 2021— Economics (Market Demand & Related Goods)
🧷 Classroom Explanation | IAS Monk Standard Format
📌 Consider the following statements: Other things remaining unchanged, market demand for a good might increase if
- price of its substitute increases
- price of its complement increases
- the good is an inferior good and income of the consumers increases
- its price falls
📌 Which of the above statements are correct?
(a) 1 and 4 only
(b) 2, 3 and 4
(c) 1, 3 and 4
(d) 1, 2 and 3
📌 Answer: (a)
🧠 Classroom Explanation
🔹 Core Concept: Determinants of Demand
Market demand for a good depends on:
- Its own price
- Prices of related goods (substitutes & complements)
- Income of consumers
- Tastes, expectations, population, etc.
The question explicitly says “other things remaining unchanged” (ceteris paribus), so we isolate the effect of each factor.
🔍 Statement-wise Analysis
✅ Statement 1: Price of its substitute increases — Correct
- Substitutes are goods that can replace each other (e.g., tea & coffee).
- If the price of coffee increases, consumers shift to tea.
- Hence, demand for the good increases.
✔️ Correct.
❌ Statement 2: Price of its complement increases — Incorrect
- Complements are goods consumed together (e.g., tea & sugar).
- If the price of sugar increases, consumption of tea falls.
- Therefore, demand decreases, not increases.
❌ Incorrect.
❌ Statement 3: Inferior good & income increases — Incorrect
- Inferior goods show an inverse relationship with income.
- When income rises, consumers shift to better alternatives.
- Hence, demand for inferior goods falls, not rises.
❌ Incorrect.
✅ Statement 4: Its price falls — Correct
- As per the Law of Demand, price and quantity demanded are inversely related.
- Fall in price → increase in quantity demanded.
✔️ Correct.
✅ Final Answer Logic
Correct statements: 1 and 4 only
➡️ Correct answer: (a)
🔍 Curiosity Raiser
Why do some goods stop behaving as inferior goods once income crosses a certain threshold?
🧘 IAS Monk Whisper
Demand is not just about price;
it listens quietly to income, choices, and alternatives.
