Shamrock Aircraft sells a wide variety of model aircraft and uses a perpetual inventory system. On Ju 1, Shamrock Aircraft had five Cessna 560 model airplanes on hand at a unit cost of $81. During June and July, company had the following purchases and sales for this airplane (all for cash): Instructions: a) Calculate the cost of ending inventory ($), cost of goods sold (\$) for the period and gross profit (\$) for the period under the weighted average method. b) Calculate the cost of ending inventory (\$), cost of goods sold (\$) for the period and gross profit (\$) for the period under the first-in-first-out (FIFO) method