KASNEB · FoundationEconomicsBETA — flag if wrong

Elasticity of Demand and Supply

This topic focuses on the concept of elasticity, measuring how responsive quantity demanded or supplied is to changes in price.

3objectives

3revision lessons

12practice questions

What you’ll learn

Aligned to the KASNEB Economics syllabus.

CF13.3.A Define price elasticity of demand and supply.
CF13.3.B Calculate the price elasticity of demand and supply using numerical examples.
CF13.3.C Distinguish between elastic, inelastic, and unitary elasticity.

Defining Price Elasticity of Demand and Supply

BETA — flag if wrongAI 100

Price elasticity of demand (PED) measures the responsiveness of quantity demanded to a change in price. It is calculated as the percentage change in quantity demanded divided by the percentage change in price. A PED greater than 1 indicates elastic demand, while a PED less than 1 indicates inelastic demand. Factors influencing PED include the availability of substitutes, necessity versus luxury status, and time period under consideration.

Price elasticity of supply (PES) measures the responsiveness of quantity supplied to a change in price. It is calculated similarly to PED, as the percentage change in quantity supplied divided by the percentage change in price. A PES greater than 1 indicates elastic supply, while a PES less than 1 indicates inelastic supply. Factors influencing PES include production time, the availability of raw materials, and the flexibility of the production process.

Understanding elasticity is crucial for businesses and policymakers in Kenya, as it informs pricing strategies, taxation policies, and subsidy decisions. For example, if the demand for maize flour (a staple in Kenya) is elastic, a price increase may lead to a significant drop in quantity demanded, affecting producers and consumers alike.

Key points

PED measures quantity demanded responsiveness to price changes.
PES measures quantity supplied responsiveness to price changes.
Factors influencing PED include substitutes and necessity status.
Factors influencing PES include production time and material availability.
Elasticity informs pricing strategies and economic policies.

Worked example

Example Calculation of Price Elasticity of Demand

Assume the price of a commodity increases from KES 80 to KES 100, and the quantity demanded increases from 20 units to 30 units.

Calculate the percentage change in quantity demanded:
- Change in quantity = 30 - 20 = 10 units
- Percentage change in quantity = (10 / 20) * 100 = 50%
Calculate the percentage change in price:
- Change in price = 100 - 80 = 20 KES
- Percentage change in price = (20 / 80) * 100 = 25%
Calculate PED:
- PED = Percentage change in quantity demanded / Percentage change in price
- PED = 50% / 25% = 2.0

Example Calculation of Price Elasticity of Supply

Assume the price of a commodity increases from KES 50 to KES 70, and the quantity supplied increases from 40 units to 60 units.

Calculate the percentage change in quantity supplied:
- Change in quantity = 60 - 40 = 20 units
- Percentage change in quantity = (20 / 40) * 100 = 50%
Calculate the percentage change in price:
- Change in price = 70 - 50 = 20 KES
- Percentage change in price = (20 / 50) * 100 = 40%
Calculate PES:
- PES = Percentage change in quantity supplied / Percentage change in price
- PES = 50% / 40% = 1.25

Both calculations show how demand and supply respond to price changes.

More on this topic

CF13.3.B Calculating Price Elasticity of Demand and SupplyBETA — flag if wrongAI 100

Price elasticity of demand (PED) measures how the quantity demanded of a good responds to a change in its price. It is calculated using the formula:

\[ PED = \frac{\text{Percentage change in quantity demanded}}{\text{Percentage change in price}} \]

For arc elasticity, the formula is:

\[ PED = \frac{(Q_2 - Q_1) / (Q_1 + Q_2)/2}{(P_2 - P_1) / (P_1 + P_2)/2} \]

Where:
- \( Q_1 \) and \( Q_2 \) are initial and new quantities demanded,
- \( P_1 \) and \( P_2 \) are initial and new prices.

Price elasticity of supply (PES) measures how the quantity supplied responds to a price change, calculated similarly:

\[ PES = \frac{\text{Percentage change in quantity supplied}}{\text{Percentage change in price}} \]

Factors influencing elasticity include availability of substitutes, time period, production capacity, and nature of the product. For example, agricultural commodities often have low elasticity due to time constraints in production.

Understanding elasticity is crucial for businesses in pricing strategies and for policymakers in economic planning.

CF13.3.C Understanding Elasticity of Demand and SupplyBETA — flag if wrongAI 100

Elasticity measures how quantity demanded or supplied responds to price changes. It is crucial for businesses in Kenya to understand these concepts for pricing strategies.

1. Elastic Demand: Demand is elastic when a small change in price leads to a significant change in quantity demanded. The price elasticity of demand (PED) is greater than 1. For example, luxury goods often exhibit elastic demand.

2. Inelastic Demand: Demand is inelastic when changes in price have little effect on quantity demanded. The PED is less than 1. Necessities such as basic food items often show inelastic demand.

3. Unitary Elastic Demand: Demand is unitary elastic when a change in price results in a proportional change in quantity demanded. The PED equals 1. This is a rare occurrence in the market.

4. Elastic Supply: Supply is elastic when producers can increase output quickly in response to price changes. This is common in industries with flexible production processes.

5. Inelastic Supply: Supply is inelastic when it is difficult for producers to change output levels quickly. Agricultural products often show inelastic supply due to factors like perishability and gestation periods.

Understanding these elasticities helps in making informed decisions regarding pricing, taxation, and market strategies.

Sample KASNEB-style questions

3 of 12 questions. Beta-flagged questions are AI-drafted and pending CPA review — flag anything that looks wrong.

Q1 · MCQ · easyBETA — flag if wrongAI 100

What does a price elasticity of demand greater than 1 indicate?

A.A. Demand is elastic.✓ correct
B.B. Demand is inelastic.
C.C. Demand is unitary elastic.
D.D. Demand is perfectly inelastic.

Q2 · MCQ · mediumBETA — flag if wrongAI 80

Which of the following factors does NOT influence the price elasticity of supply?

A.A. Time period for production.
B.B. Availability of raw materials.
C.C. Consumer preferences.✓ correct
D.D. Production capacity.

Q3 · SHORT ANSWER · mediumBETA — flag if wrongAI 93

Define price elasticity of demand and explain two factors that affect it.

Model answer

Price elasticity of demand measures how much the quantity demanded of a good responds to a change in the price of that good. 1. Availability of substitutes: More substitutes make demand more elastic. 2. Necessity vs luxury: Necessities tend to have inelastic demand, while luxuries tend to have elastic demand.

Practice the full question bank with the AI tutor

12 questions on this topic alone. Get feedback after every attempt; the tutor re-explains what you got wrong. Beta access is free.

Reserve beta access

Common questions

Define price elasticity of demand and supply.

PED measures quantity demanded responsiveness to price changes.

Calculate the price elasticity of demand and supply using numerical examples.

PED measures quantity demanded response to price changes.

Distinguish between elastic, inelastic, and unitary elasticity.

Elastic demand: PED > 1, significant response to price changes.