How would you solve the following problem?

Cost flow assumptions—FIFO and LIFO using a periodic system The beginning inventory was 600 units at a cost of $20 per unit. Goods available for sale during the year were 2,600 units at a total cost of $57,600. In May, 1,200 units were purchased at a total cost of $26,400. The only other purchase transaction occurred during October. Ending inventory was 1,100 units. Page 167 Required:

a. Calculate the number of units purchased in October and the cost per unit purchased in October.

b. Calculate cost of goods sold and ending inventory under the following cost flow assumptions (using a periodic inventory system): FIFO LIFO