help with the incorrect please

Joe's Products sold 170 units at $30/ unit during the quarter. Of the untis sold, 20 came from beginning inventory, 30 came from the Feb. 15 purchase, and 50 came form the March 15 purchase with the remaining units coming from Jan. 15. Fill out the table below with the COGS, Ending Inventory, and Gross Margin under the four different inventory flow assumptions