Bruce Corporation makes four products in a single facility. These products have the following unit product costs: Products A B C D Direct materials $ 15.50 $ 11.40 $ 12.20 $ 11.80 Direct labor 20.60 28.60 34.80 41.60 Variable manufacturing overhead 5.50 3.90 3.80 4.40 Fixed manufacturing overhead 27.70 36.00 27.80 38.40 Unit product cost $ 69.30 $ 79.90 $ 78.60 $ 96.20 Additional data concerning these products are listed below. Products A B C D Grinding minutes per unit 5.00 6.50 5.50 4.60 Selling price per unit $ 77.30 $ 94.70 $ 88.60 $ 105.40 Variable selling cost per unit $ 3.40 $ 2.40 $ 4.50 $ 2.80 Monthly demand in units 5,200 5,200 4,200 3,200 The grinding machines are potentially the constraint in the production facility. A total of 54,800 minutes are available per month on these machines. Direct labor is a variable cost in this company. How many minutes of grinding machine time would be required to satisfy demand for all four products