Response to the following problem:
The inventory data for an item for September are: Sep. 1 Inventory 20 units at $20 4 Sold 10 units 10 Purchased 30 units at $25 17 Sold 20 units 30 Purchased 10 units at $30 17. Using the perpetual system, costing by the first-in, first-out method, what is the cost of the merchandise inventory of 30 units on September 30?