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Price Elasticity of Demand Numericals for Class 11 with Solutions

Price elasticity becomes easier when you separate the change in quantity, change in price and the original base values before substituting. This toolkit combines worked numericals with the free PED calculator so you can solve first and verify second.

Formula map

  • Percentage Method: Ed = (ΔQ ÷ ΔP) × (P ÷ Q) — Use original price and quantity as the base when the question uses the percentage method.
  • Magnitude: |Ed| > 1 elastic; |Ed| = 1 unitary; |Ed| < 1 inelastic — Demand usually gives a negative coefficient because price and quantity demanded move inversely; classification uses magnitude.
  • Total Expenditure: TE = Price × Quantity Demanded — Compare how total expenditure changes when price changes.

10 solved numericals with steps

These are original learning problems prepared for practice and are not labelled as official CBSE previous-year questions.

Q1. Unitary Elastic Demand — Basic

Price falls from ₹10 to ₹8 and quantity demanded rises from 100 to 120 units. Find Ed by percentage method.

  1. ΔQ = 20; ΔP = −2
  2. Ed = (20 ÷ −2) × (10 ÷ 100) = −1

Answer: |Ed| = 1; unitary elastic demand

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Q2. Another Unitary Case — Basic

Price falls from ₹20 to ₹18 and quantity rises from 100 to 110 units.

  1. ΔQ = 10; ΔP = −2
  2. Ed = (10 ÷ −2) × (20 ÷ 100) = −1

Answer: |Ed| = 1; unitary elastic demand

Q3. Inelastic Demand — Basic

Price falls from ₹10 to ₹9 and quantity rises from 100 to 105 units.

  1. ΔQ = 5; ΔP = −1
  2. Ed = (5 ÷ −1) × (10 ÷ 100) = −0.5

Answer: |Ed| = 0.5; inelastic demand

Q4. Elastic Demand — Board-style

Price falls from ₹10 to ₹8 and quantity rises from 100 to 130 units.

  1. ΔQ = 30; ΔP = −2
  2. Ed = (30 ÷ −2) × (10 ÷ 100) = −1.5

Answer: |Ed| = 1.5; elastic demand

Q5. Price Rise with Inelastic Demand — Basic

Price rises from ₹5 to ₹6 and quantity falls from 200 to 180 units.

  1. ΔQ = −20; ΔP = 1
  2. Ed = (−20 ÷ 1) × (5 ÷ 200) = −0.5

Answer: |Ed| = 0.5; inelastic demand

Q6. Price Rise — Mixed

Price rises from ₹4 to ₹5 and quantity falls from 100 to 80 units.

  1. ΔQ = −20; ΔP = 1
  2. Ed = (−20 ÷ 1) × (4 ÷ 100) = −0.8

Answer: |Ed| = 0.8; inelastic demand

Q7. Larger Values — Mixed

Price rises from ₹20 to ₹25 and quantity falls from 50 to 40 units.

  1. ΔQ = −10; ΔP = 5
  2. Ed = (−10 ÷ 5) × (20 ÷ 50) = −0.8

Answer: |Ed| = 0.8; inelastic demand

Q8. Constant Total Expenditure — Expenditure method

Price falls from ₹10 to ₹8 while quantity rises from 100 to 125 units. Classify elasticity using total expenditure.

  1. Old TE = 10 × 100 = 1,000
  2. New TE = 8 × 125 = 1,000
  3. TE remains constant when price changes

Answer: Unitary elastic demand

Q9. Elastic by Total Expenditure — Expenditure method

Price falls from ₹10 to ₹8 and quantity rises from 100 to 140 units.

  1. Old TE = 1,000
  2. New TE = 8 × 140 = 1,120
  3. Price falls while total expenditure rises

Answer: Elastic demand

Q10. Inelastic by Total Expenditure — Expenditure method

Price falls from ₹10 to ₹8 and quantity rises from 100 to 110 units.

  1. Old TE = 1,000
  2. New TE = 8 × 110 = 880
  3. Price falls while total expenditure falls

Answer: Inelastic demand

Quick self-test

  1. P: 10→8; Q: 100→110. Find |Ed| by percentage method. Answer: 0.5
  2. P: 20→16; Q: 100→130. Find |Ed|. Answer: 1.5
  3. Old TE ₹500 and new TE ₹500 after a price change. Classification? Answer: Unitary elastic
  4. Price falls and total expenditure rises. Classification? Answer: Elastic demand
  5. Price rises and total expenditure also rises. Classification? Answer: Inelastic demand

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Topics covered

  • Percentage method
  • Absolute magnitude of elasticity
  • Elastic, unitary and inelastic demand
  • Total expenditure method
  • Sign and interpretation
  • Common base-value mistakes

Calculators in this toolkit

Frequently asked questions

Why can price elasticity of demand be negative?

Price and quantity demanded usually move in opposite directions, so the coefficient can be negative. Many school questions classify elasticity using its absolute magnitude.

Which values are used as the base in the percentage method here?

The calculator and worked examples use original price and original quantity as the base values.

How should I practise elasticity numericals?

Write ΔQ and ΔP first, write the formula, substitute carefully, classify the absolute magnitude and then verify using the calculator.

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