Black Company uses the weighted-average method in its process costing system. The company's ending work-in proess inventory consists of 6,000 units, 75 percent complete with respect to materials and 50 percent complete with respect to laor and overhead. If the total dollar value of the inventory is $80,000 and the cost per equivalent unit for labor and overhead is $6.00, what is the cost per equivalent unit for materials? Please show how to compute.