After graduating from dental school two years ago, Dr. Lauren Farish purchased the dental practice of a long-time dentist who was retiring. In January of this year, she had to replace the outdated autoclave equipment she inherited from the previous dentist. Now, as she is preparing her budget for next year, she is concerned about understanding how her cost for sterilizing her dental instruments has changed. She has gathered the following information from her records: Month Number of instruments used Total autoclave cost January 850 $7,600 February 750 6,800 March 920 8,200 April 950 8,600 May 1,150 9,900 June 900 8,100 July 1,050 9,600 August 975 8,700 Identify the high and low points. Activity Level ta High point $ Low point ta Using the high-low method, what is the variable cost of sterilizing an instrument using the new equipment? (Round answer to 2 decimal places, e.g. 52.75.) Variable cost ta $ per instrument