All sales are on credit. Historically, 50 percent is collected in the month of sale, 35 percent during the first month following the sale, and 15 percent in the second month following the sale. Water purchases by month are as follows: Month SLle 5 February $37,5 00 March 33,7 50 April 45,0 00 May 31,8 75 June 52,5 00 July 90, 000 Water is purchased in the month of sale. All purchases are paid during the month following the purchase