EXERCISE The following information was available from the inventory records of Rich Company for January: Units Unit Cost Total Cost Balance at January 1 3,000 $9,77 $29,310 Purchases: January 6 2,000 10.30 20,600 January 26 2,700 10.71 28,917 Sales: January 7 (2,500) January 31 (4,000) Balance at January 31 1,200 1. Calculate COGS and ending inventory using periodic weighted average method 1. Calculate COGS and ending inventory using perpetual weighted average method