Presented below is the production data for the first six months of the year for the mixed costs incurred by Strongsville Company. Month Cost Units January $7,500 4,000 February 13,000 6,500 March 10,500 8,000 April 12,700 10,500 May 13,500 12,000 June 10,850 9,000 Strongsville Company uses the high‐low method to analyze mixed costs. The variable cost per unit is: