Exhibit 5 graphically displays the revenue data from perfect competition. For an individual firm operating in a market setting of perfect competition, MR equals AR and both are equal to a price that stays the same across all levels of output. Because price is fixed to the individual seller, the firm’s demand curve is a horizontal line at the point where the market sets the price. In Exhibit 5, at a price of 100, P₁ = MR₁ = AR₁ = Demand₁. Marginal revenue, average revenue, and the firm’s price remain constant until market demand and supply factors cause a change in price. For instance, if price increases to 200 because of an increase in market demand, the firm’s demand curve shifts from Demand₁ to Demand₂ with corresponding increases in MR and AR as well. Total revenue increases from TR₁ to TR₂ when price increases from 100 to 200. At a price of 100, total revenue at 10 units is 1,000; however, at a price of 200, total revenue would be 2,000 for 10 units.