Current Attempt in Progress Cullumber Company accumulates the following data concerning a mixed cost, using miles as the activity level. Miles Driven Total Miles Total Cost Driven: Co January 6,720 $11,880 March 7,140 $12,600 February 6,300 11,340 April 6,880 12,172 (a1) Compute the variable cost per mile using the high-low method. (Round answer to 2 decimal places, e.g. 2.25.) Variable cost per mile $