what is the variable cost per unit?

The Junior League of Yadkinville, California, collected recipes from members and published a cookbook entitled Food for Everyone. The book will sell for $19 per copy. The chairwoman of the cookbook development committee estimated that the club needed to sell 5,800 books to break even on its $40,600 investment. What is the variable cost per unit assumed in the Junior League's analysis? (Round your answer to the nearest whole number.) $x per unit