If the demand for a good is elastic, what is true?

Price elasticity of demand measures how much the quantity demanded of a good responds to a change in its price. If demand is elastic, it means the percentage change in quantity demanded is greater than the percentage change in price. In simple terms, consumers are highly responsive to price changes; a small change in price leads to a substantial change in the quantity they are willing to buy.

B. For elastic demand, total revenue moves in the opposite direction of a price change. A price increase reduces total revenue.

C. Price and total revenue move in the same direction only when demand is inelastic, not elastic.

D. A slight response in quantity demanded to a price change is the definition of inelastic demand, not elastic demand.

1. Mankiw, N. G. (2021). Principles of Economics (9th ed.). Cengage Learning. Chapter 5, Section 5-1a, "The Price Elasticity of Demand and Its Determinants," defines elastic demand as a situation where the quantity demanded responds substantially to changes in the price.

2. Krugman, P., & Wells, R. (2018). Economics (5th ed.). Worth Publishers. Chapter 6, "Defining and Measuring Elasticity," states that demand is elastic if the price elasticity of demand is greater than 1, indicating a high responsiveness of quantity demanded to price (p. 167).

3. MIT OpenCourseWare. (2018). 14.01 Principles of Microeconomics, Lecture 4: Elasticity. The lecture defines elastic demand as |Ed| > 1, signifying that a 1% change in price leads to a more than 1% change in quantity demanded.