from where does the 1200 units came from?

FIFO FIFO Date of purchase Purchase rate Quantity Total Beginning inventory $ 8.00 1.900 15.200 Apr-04 S 8.25 2.900S 23.925 Apr-10 $ 8.40 4,500 $ 37.800 Apr-19 $ 9.00 1.100 9.900 Apr-29 $ 9.90 2.700$ 26,730 Goods available for sale 13.100 $ 113.555 3.900 $ Less: Ending inventory Cost of goods sold 37.530 (2700 units * $9.90)+(1200 units * $9.00); 9,200 S 76,025 LIFO LIFO Date of purchase Purchase rate Quantity Total Beginning inventory $ 8.00 1.900$ 15.200 Apr-04 8.25 2.900 $ 23.925 Apr-10 $ 8.40 4,500 $ 37.800 Apr-19 $ 9.00 1.100 S 9.900 Apr-29 $ 9.90 2.700$ 26.730 Goods available for sale 13.100 S 113.555 3.900$ 31.700(1900 units * $ 8.00)+(2000 units 8.25)} Less: Ending inventory Cost of goods sold 9,200 S 81,855 Average cost method Date of purchase Purchase rate Quantity Total Beginning inventory $ 8.00 1.900 $ 15.200 Apr-04 8.25 2.900 $ 23.925 Apr-10 $ 8.40 4.500 $ 37,800 Apr-19 9.00 1.100 S 9.900 Apr-29 $ 9.90 2.700 $ 26.730 Goods available for sale 13.100 $ 113.555 Average cost per unit $ 8.67 ($ 113.555/13,100 uits) 33.806 8.67. 3900 units Less:Ending inventory 3.900S Cost of goods sold 9.2005 79,749