Suppose that a small town has seven burger shops whose respective shares of the local hamburger market are (as percentages of all hamburgers sold): 26%, 25%, 20%, 12%, 9%, 5%, and 3%. What is the four-firm concentration ratio of the hamburger industry in this town? % What is the Herfindahl index for the hamburger industry in this town? If the top three sellers combined to form a single firm, what would happen to the four-firm concentration ratio and to the Herfindahl index? The four-firm concentration ratio would be %. The Herfindahl index would be ?