The document discusses price elasticity of demand (PED), which measures the responsiveness of demand for a good or service to a change in price. It provides examples of calculating PED and determining whether a product is elastic or inelastic based on the value of PED. An inelastic PED between 0 and -1 means demand is not very responsive to price changes, while an elastic PED between -1 and infinity means demand is highly responsive. The document also demonstrates how companies can use PED to determine whether a price increase or decrease would increase total revenue by calculating the impact on sales volume and multiplying it by the new price.