Sumter Company uses the weighted-average method in its process costing system. The fol lowing data pertain to operations in the first processing department. Work in process, beginning: Units in process Percent complete with respect to materi at.. Percent complete with respect to conversion 6,000 60% 20% Costs in the beginning inventory: Materials cost Conversion cost.. $78,200 S3,600 Units started during the month... Units completed and transferred out during the month.0,000 Costs added to production during the month: Materials cost Conversion cost ..$286,600 $216,000 Work in process, ending: Units in process. Percent complete with respect to materials. 8,000 75% 25% Percent complete with respect to conversion