Sheridan Corporation purchased a tract of unimproved land for $564,000. This land was improved and subdivided into building lots at an additional cost of $117,000. These building lots were all of the same size but owing to differences in location were offered for sale at different prices as follows: Group No. of Lots Price per Lot 1 21 $23,700 2 13 18,600 3 9 16,300 Operating expenses for the year allocated to this project total $71.900. Lats unsold at the year-end were as follows: Group 1 9 lots Group 2 3 lots Group3 4 lots