Final answer:
Price elasticity of demand measures the responsiveness of quantity demanded to changes in price, represented as the ratio of percentage changes in quantity demanded to percentage changes in price.
Step-by-step explanation:
The concept of price elasticity of demand is best described as the percentage change in the quantity demanded of a good or service divided by the percentage change in the price. It is a measure of how much the quantity demanded of a product changes in response to a change in price. When calculating the price elasticity of demand, the result can show us whether demand for the product is perfectly inelastic, inelastic, unit elastic, or elastic.