1. Ten firms compete in a market to sell product X. The total sales of all firms selling the product are $1,000,000. Ranking the firms' sales from highest to lowest, we find the top four firms' sales to be $160,000, $105,000, $95,000, and $80,000, respectively. Calculate the four-firm concentration ratio in the market for product X. Enter your response rounded to two decimal places.

2. An industry consists of three firms with sales of $180,000, $425,000, and $115,000. a. Calculate the Herfindahl-Hirschman index (HHI). Instruction: Enter your response rounded 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 $180,000 and $115,000?

• No
• Yes