Suppose that a small town has seven burger shops whose respective shares of the local hamburger market are (as percentages of all hamburgers sold): 23 percent, 22 percent, 18 percent, 12 percent, 11 percent, 8 percent,and 6 percent. 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?