The beginning inventory was 340 units at a cost of $13 per unit. Goods available for sale during the year were 1,420 units at a total cost of $19 , 980 . In May, 640 units were purchased at a total cost of $8 , 960 . The only other purchase transaction occurred during October. Ending inventory was 610 units. Requlred: a. Calculate the number of units purchased in October and the cost per unit purchased in October. b-1. Assume the periodic inventory system is used. Calculate cost of goods sold and ending inventory using FIFO method. (Enter all values as a positive value.) b-2. Assume the periodic inventory system is used. Calculate cost of goods sold and ending inventory using LIFO method. (Enter all values as a positive value.).