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Economics 3% exam weight

Consumer Behaviour

Part of the RPSC RAS study roadmap. Economics topic econom-004 of Economics.

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Consumer Behaviour

🟢 Lite — Quick Review (1h–1d)

Rapid summary for last-minute revision before your exam.

Consumer Behaviour — Key Facts for RPSC RAS Core concept: How consumers make decisions to spend their limited income on goods and services High-yield point: Law of Demand, Consumer’s Equilibrium via Utility Analysis, and Indifference Curve Analysis ⚡ Exam tip: Diagram-based questions on Budget Line and Indifference Curves are frequently asked in RPSC RAS

🟡 Standard — Regular Study (2d–2mo)

Standard content for students with a few days to months.

Consumer Behaviour — RPSC RAS Study Guide

Cardinal Utility Approach (Marshall):

  • Utility: Satisfaction derived from consuming a good
  • Law of Diminishing Marginal Utility: MU decreases as consumption increases
  • Consumer’s Equilibrium: MU = Price, until budget is exhausted
  • Limitation: Ignores substitutability and multi-product consumption

Ordinal Utility Approach (Hicks):

  • Indifference Curve: Shows combinations giving equal satisfaction (downward sloping, convex)
  • Marginal Rate of Substitution (MRS): Rate at which consumer substitutes X for Y
  • Budget Line: All affordable combinations (slope = Px/Py)
  • Consumer’s Equilibrium: Highest indifference curve touching the budget line

Key Concepts:

  • Price Effect = Income Effect + Substitution Effect
  • Normal Goods: Income effect positive
  • Inferior Goods: Negative income effect (Giffen goods are extreme case)
  • Composite Good: All other goods taken together

RPSC RAS Specific:

  • Previous year questions focus on Marshallian vs Hicksian analysis
  • Diagram questions on Consumer Equilibrium are high-scoring
  • Numerical problems on Elasticity of Demand frequently appear

🔴 Extended — Deep Study (3mo+)

Comprehensive coverage for students on a longer study timeline.

Consumer Behaviour — Comprehensive RPSC RAS Notes

1. Cardinal Utility Analysis:

  • Total Utility (TU): Sum of marginal utilities
  • MU = ∂TU/∂Q
  • At equilibrium: ΣMU = Budget (for multiple goods)
  • Critical assumptions: Rational consumer, diminishing MU, constant marginal utility of money

2. Ordinal Utility Analysis (Indifference Curve):

  • Properties of IC: Downward sloping, convex, non-intersecting, higher = better
  • MRSxy = ΔY/ΔX (with sign reversed)
  • Budget Constraint: Px.X + Py.Y = M
  • Interior solution: MRSxy = Px/Py

3. Demand Theory:

  • Law of Demand: P↑ → Qd↓ (ceteris paribus)
  • Exceptions: Giffen goods, Veblen goods, speculative demand
  • Elasticity of Demand: Ed = %ΔQd / %ΔP
  • Types: Ep > 1 (elastic), Ep = 1 (unitary), Ep < 1 (inelastic), Ep = 0 (perfectly inelastic), Ep = ∞ (perfectly elastic)

4. Consumer’s Surplus:

  • CS = What consumer pays − What consumer would pay
  • Marshall’s measure: Area between demand curve and price line
  • Limitations: Ignores income effects, assumes constant MU of money

5. RPSC RAS Exam Pattern:

  • 2-3 questions from Consumer Behaviour (3-6 marks)
  • Common questions: MRS calculation, Consumer equilibrium (utility approach), Price/Income/Substitution effects
  • Suggested reading: Modern Economics by H.L. Ahuja, Unit 3-4

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