Bargain Rental Car offers rental cars in an off-airport location near a major tourist destination in California. Management would like to better understand the variable and fixed portions of its car washing costs. The company operates its own car wash facility in which each rental car that is returned is thoroughly cleaned before being released for rental to another customer. Management believes that the variable portion of its car washing costs relates to the number of rental returns. Accordingly, the following data have been compiled: Month Rental Returns Car Wash Costs January 2,300 $ 10,400 February 2,500 $ 12,800 March 2,700 $ 11,200 April 2,900. $ 13,400 May 3,600 $ 15,600 June 4,900 $ 22,100 July 5,500 $ 21,600 August 5,300 $ 20,700 September 4,700 $ 22,200 October 3,800 $ 19,300 November 2,100 $ 10,100 December 2,600 $ 12,100