Bargain Rental Car wants to better understand the variable and fixed portions of its car washing costs. The company operates its own car wash facility that cleans each rental car before releasing it to another customer. Management believes the variable portion of its car washing costs relates to the number of rental returns. Accordingly, the following data have been compiled: Rental Month Returns Car Wash Costs January 2,380 $ 10,825 February 2,421 $ 11,865 March 2,586 $ 11,332 April 2,725 $ 12,422 May 2,968 $ 13,850 June 3,281 $ 14,419 July 3,353 $ 14,935 August 3,489 $ 15,738 September 3,057 $ 13,563 October 2,876 $ 11,889 November 2,735 $ 12,683 December 2,983 $ 13,796