Part A)Assume an industry has 18 firms. Top two firms have the market share 10 percent each and rest of the sixteen firms have market shares 5 percent each. Herfindahl index in this industry is equal to:

Part B) Assume an industry has 18 firms. Top two firms have the market share 10 percent each and rest of the sixteen firms have market shares 5 percent each. Four-firms concentration ratio in this industry is equal to: