I need to know if this is right and i also need to know how to determine the cost assigned to the dec. 31 ending inventory when costs are assigned based on (a) fifo, (b) lifo (c) weight average and (d) specific identification can some one explain to me how to do this . Also let me know if what I have done is correct so far.

December 7 10 units @<hidden> 6.oo = $60
December 14 20 units @<hidden> 12.00 cost = $240

Total Inventory = 240 + 60 = $300 / 30 units = $10 per unit

December 15, sold 15 units

December 21 15 units @<hidden> 14.00 cost = $210


Inventory left:
After Dec. 15 Sale = 15 units at $10 each = $150
Plus Dec. 21 Purchase of $210

Total Inventory left = 210 + 150 = $360

Ending Inventory value. So therefore, that makes its $360.