please help answer part B. part a is done. thanx

Question 1 of 4 0.5/1 E View Policies Show Attempt History Current Attempt in Progress Skysong Company uses a periodic inventory system. For April, when the company sold 600 units, the following information is available Units April 1 inventory April 15 purchase April 23 purchase 270 410 320 1.000 Unit Cost $16 19 21 Total Cost $ 4,320 7.790 6.720 $18,830 Your answer is correct. Calculate weighted average cost per unit. (Round answer to 2 decimal places, es. 2.76) Weighted average cost per unit $ 18.83 (b) x Your answer is incorrect Compute the April 30 inventory and the April cost of goods sold using the average-cost method (Round answers to decimal places, eg. 2,760.) $ 8240 Ending inventory Cost of goods sold $ 10590 Question 1 of 4 0.5/1 E View Policies Show Attempt History Current Attempt in Progress Skysong Company uses a periodic inventory system. For April, when the company sold 600 units, the following information is available Units April 1 inventory April 15 purchase April 23 purchase 270 410 320 1.000 Unit Cost $16 19 21 Total Cost $ 4,320 7.790 6.720 $18,830 Your answer is correct. Calculate weighted average cost per unit. (Round answer to 2 decimal places, es. 2.76) Weighted average cost per unit $ 18.83 (b) x Your answer is incorrect Compute the April 30 inventory and the April cost of goods sold using the average-cost method (Round answers to decimal places, eg. 2,760.) $ 8240 Ending inventory Cost of goods sold $ 10590