Three of the following are part of the NCERT explanation of why the MRS falls as a consumer gets more bananas along an indifference curve. Which one is the odd one out?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → The price of bananas falls as she buys more of them
The MRS falls because of how the consumer values the two goods as her bundle changes.
Option (1) The marginal utility of mangoes rises as she has fewer of them — True. Each mango left is worth more to her.
Option (2) The price of bananas falls as she buys more of them — False. Prices are given in the market and do not change along an indifference curve.
Option (3) The marginal utility of each additional banana falls — True. Each extra banana adds less satisfaction.
Option (4) She is willing to give up smaller and smaller amounts of mangoes — True. This is the falling MRS itself.
NCERT (2026-27): “2.1.2 Ordinal Utility Analysis … As the number of bananas with the consumer increases, the MU derived from each additional banana falls. Similarly, with the fall in quantity of mangoes, the marginal utility derived from mangoes increases. So, with increase in the number of bananas, the consumer will feel the inclination to sacrifice small and smaller amounts of mangoes. This tendency for the MRS to fall with increase in quantity of bananas is known as Law of Diminishing Marginal Rate of Substitution. …” |