An industry consists of three firms with sales of $175,000, $555,000, and $205,000.
a. Calculate the Herfindahl-Hirschman index (HHI). Instruction: Round to the nearest integer.
b. Calculate the four-firm concentration ratio (C4).
c. Based on the FTC and DOJ Horizontal Merger Guidelines described in the text, is the Department of Justice likely to attempt to block a horizontal merger between two firms with sales of $175,000 and $205,000?