Ivanhoe Corp. has collected the following data concerning its maintenance costs for the past 6 months. Units Total Cost Produced July 15,480 $30,960 August 27,520 41,280 September 30,960 47,300 October 18,920 32,680 November 34,400 64,070 December 32,680 53,320 (a1) Compute the variable cost per unit using the high-low method. (Round answer to 2 decimal places, e.g. 2.25.) Variable cost per unit $