Saddlery Company sells leather saddles and equipment for horse enthusiasts. Saddlery uses the perpetual inventory system. The following schedule relates to the companys inventory for the month of May:

						Cost		Sales
May 1		Beginning inventory		150 units		$52,500
5		Sale		100 units				$45,500
9		Purchase		50 units		$19,250
13		Purchase		200 units		$84,000
24		Sale		200 units				$98,000
27		Sale		50 units				$28,000
30		Purchase		75 units		$34,650

Please identify the COGS, Gross margin, Gross Margin ratio and ending inventory using weighted average.