Can you explain how they calculated average production cost? I am not understanding where the 857 came from or the 12, 576?

2. How much does it cost to produce each product? Price per Ibs = 169/21.42 = $8 Items Sales per unit Weight Lbs. Cost per lbs $ Cost per unit $ Average weekly $ production cost $ Patterned 9 5 8 4 76 glasses Paperweights 15 8 7.2 72 Wrapped 8 5 8 4 128 tumblers Vases 25 . 6 8 4.8 38.4 3. How much is the per unit profit of each product? Items Sales per unit $ Less Costs Profit per unit $ Fixed cost Variable Cost Total cost per per unit $ per unit $ unit $ Patterned glasses 9 14.78 4 18.78 (9.78) Paperweights 15 14.78 7.2 21.98 (6.98) Wrapped tumblers 8 14.78 4 18.78 (10.78 Vases 25 14.78 4.8 19.58 5.42 Fixed Cost = Total Cost (less) Variable Cost = ($52,510 + 857) - 12,576 = 40,791 Manufacturing units per year = 2760