Gladstone Limited tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method at the end of each period, as if it uses a periodic inventory system. Assume its accounting records provided the following information at the end of the annual accounting period, December $31.$

Transactions Units Unit Cost

Beginning inventory, January $11,900$ $ $4\mathrm{.}00$

Transactions during the year:

a$.$ Purchase, January $302,5006\mathrm{.}00$

b$.$ Sale, March $14($$$10$ each$)(1,500)$

c$.$ Purchase, May $11,2008\mathrm{.}00$

d$.$ Sale, August $31($$$10$ each$)(1,900)$

Required:

$1.$ Compute the amount of goods available for sale, ending inventory, and cost of goods sold at December $31,$ under each of the following inventory costing methods. For Specific identification, assuming that the March $14,$ sale was selected two$-$fifths from the beginning inventory and three$-$fifths from the purchase of January $30.$ Assume that the sale of August $31,$ was selected from the remainder of the beginning inventory, with the balance from the purchase of May $1.$