The following information is available for a company's cost of sales over the last four months. Month January February March April Units Sold 470 870 1,950 2,750 Total Costs $ 33,800 $ 40,500 $ 52,500 $ 64,500 Using the high-low method, the estimated variable cost of sales per unit sold is: Multiple Choice $23.45. $71.91 $30.53