Brief Exercise 18-5 a1-a2 Ivanhoe Corp. has collected the following data concerning its maintenance costs for the past 6 months. Units Produced Total Cost July 18,700 $39,712 August 33,344 50,016 September 37,512 57,310 October 22,924 40,126 November 41,680 77,629 December 39,596 64,604 (a1) Compute the variable cost per unit using the high-low method.