Question

Discuss the law of diminishing marginal rate of substitution with the help of diagram.

Answer 1

The Law of Diminishing Marginal Rate of Substitution is a key idea in consumer theory, and it is strongly related to the shape of Indifference Curves. It explains why these curves are usually convex towards the origin.

The Marginal Rate of Substitution (MRS) is the rate at which a consumer is willing to replace one good with another while keeping the same overall level of satisfaction or utility.

`MRS_(XY) = -(DeltaY)/(DeltaX)`

where:

1. MRS_xy = Marginal Rate of Substitution of X for Y
2. ΔY = Units of Good Y given up
3. ΔX = Units of Good X gained

According to the law, as a consumer consumes more units of one good (say X) instead of another (say Y), the amount of Y they are prepared to sacrifice for each additional unit of X diminishes. This occurs because the more you have of one item, the less valuable each additional unit becomes in comparison to the other good.

Assumptions of the Law:

1. Rational Consumer: The consumer seeks to maximize overall satisfaction.
2. Diminishing Marginal Utility: The additional enjoyment gained from consuming an extra unit of a good decreases.
3. Divisibility of Goods: Both items can be divided into smaller units.
4. No Change in Taste and Preferences: Consumer tastes and preferences remain constant.