Total revenue, average revenue, and marginal revenue are all terms that represent how much revenue a firm gets at different quantities of output sold. Total revenue is the amount of revenue a firm receives at different quantities. P Q , where P represents the price of the product, and Q is the quantity sold. Average revenue is revenue per unit of output. Average revenue is the same as demand.
Marginal revenue is the additional revenue gained by selling one more unit of the product.
We know from our study of demand that people usually respond to price changes by changing the quantity they buy. Most people respond more to changes in the price of jeans than to changes in the price of required textbooks. Elasticity gives us a way to measure how much people respond to price changes. The price elasticity of demand is the percentage change in quantity demanded of a good divided by the percentage change in price of that good. Although the quantity demanded changes in the opposite direction from the change in price, we usually talk about the price elasticity of demand as a positive number.