the following information is available: units in process, jan. 1 (60 percent converted) 2,000 units units in process, jan. 31 (30 percent converted) 1,000 units units started during the month 7,500 units total conversion costs accounted for during the month $237,600 materials are added at the beginning of the process. what is the cost per equivalent unit for conversion in jan. using the weighted average method?