Boyce company manufactures chemicals. chemical agent abx is refined in the refining department and, after it is transferred to the mixing department, a reactive agent is added to it. in may, 25,000 gallons of abx having a cost of $100,000 were transferred from the refining to the mixing department where 15,000 gallons of the reactive agent were added. when calculating the inventory costs in the mixing department, what will the cost per unit relating to gallons transferred in from the refining department be?