BE6-3 In its fi rst month of operations, Rusch Company made three purchases of merchan- dise in the following sequence: (1) 300 units at $6, (2) 400 units at $7, and (3) 200 units at $8. Assuming there are 450 units on hand, compute the cost of the ending inventory under the (a) FIFO method and (b) average-cost method. Rusch uses a periodic inventory system