Accounting, I need hand write calculations step by step please

Ace Systems, Inc. uses a perpetual inventory system. The company's beginning inventory of a particular product and its purchases during the month of January were as follows: Unit Cost $27.50 $28.00 $29.00 Quantity Total Cost Beginning inventory (1 Jan. Purchase (15 Jan.) Purchase (23 Jan).... $275 $420 $145 $840 15 Total 30 On 28 January, Ace Systems sells 18 units (10 units from beginning inventory, 4 units from 15 Jan purchase, and 4 units from 23 Jan purchase) of this product. The other 12 units remain in inventory at 31 January 1 Refer to above data. Assuming that Ace Systems uses the weighted average cost flow assumption, the cost of goods sold to be recorded at 28 January is: a $504 b $336 c $499. d Some other amount. 2 Refer to above data. Assuming that Ace Systems uses the specific cost identification method, the cost of goods sold on 28 January is a S331. b $503. $509. d Some other amount. 3 Refer to above data. Assuming that Ace Systems uses the FIFO flow assumption, the cost of goods sold on 28 January is: a $509 b S341. C S499 d Some other amount. 4 Refer to above data. Assuming that Ace Systems uses the weighted average cost flow assumption, the 12 units of this product in inventory at 31 January have a total cost of a $499 S336. ? S509 d b Some other amount. Refer to above data. Assuming that Ace Systems uses the FIFO flow assumption, the 12 units of this product in inventory at 31 January have a total cost of a S341 b S509. 5 c $499. d Some other amount