Question

Difficulty: MediumCardinal Utility Analysis and Consumer Equilibrium

A consumer allocates a fixed budget between Good XX and Good YY. Good XX sells for N40\mathbb{N}40 per unit, while Good YY sells for N15\mathbb{N}15 per unit. If the consumer obtains 160160 utils of marginal utility from the last unit of Good XX, what marginal utility must Good YY yield for the consumer to attain equilibrium?

  1. 6060 utilsAnswer
  2. B
    160160 utils
  3. C
    4040 utils
  4. D
    426.67426.67 utils

Answer

The marginal utility yielded by Good YY must be 6060 utils.
Under cardinal utility analysis, a consumer maximizes total satisfaction from a given budget when the marginal utility per monetary unit spent is equal for all commodities consumed (MUXPX=MUYPY\frac{MU_X}{P_X} = \frac{MU_Y}{P_Y}). Given MUX=160MU_X = 160 and PX=40P_X = 40, the marginal utility per Naira spent on Good XX is 16040=4\frac{160}{40} = 4. For Good YY with price PY=15P_Y = 15, setting MUY15=4\frac{MU_Y}{15} = 4 yields MUY=60MU_Y = 60 utils.

Step-by-Step Solution

1
Identify the equilibrium condition under cardinal utility analysis for two goods.
The equi-marginal condition states MUXPX=MUYPY\frac{MU_X}{P_X} = \frac{MU_Y}{P_Y}.
A rational consumer maximizes satisfaction when the marginal utility per unit of currency spent is equal across all goods.
2
Calculate the weighted marginal utility per Naira for Good XX.
\frac{MU_X}{P_X} = \frac{160}{40} = 4\text{ utils per Naira}.
This yields the satisfaction per Naira spent on Good XX.
3
Solve for the unknown marginal utility of Good YY (MUYMU_Y).
\frac{MU_Y}{15} = 4 \implies MU_Y = 4 \times 15 = 60\text{ utils}.
Equating the marginal utility per Naira spent on Good YY to 44 gives the required MUYMU_Y.

Key Concept

Principle of Equi-Marginal Utility
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