The inventory records for Radford Co. reflected the following Beginning inventory @ May 1 First purchase @ May 7 second purchase @ May 17 Third purchase @ May 23 Sales @ May 31 1,300 units@ $4.20 1,400 units@ $4.40 1,600 units@ $4.50 1,200 units@ $4.60 4, 200 units@ $6.10 Determine the weighted average cost per unit (rounded) for May