Bruce Corporation makes four products in a single facility. These products have the following unit product costs: Products A B C D Direct materials $ 14.60 $ 10.50 $ 11.30 $ 10.90 Direct labor 19.70 27.70 33.90 40.70 Variable manufacturing overhead 4.60 3.00 2.90 3.50 Fixed manufacturing overhead 26.80 35.10 26.90 37.50 Unit product cost $ 65.70 $ 76.30 $ 75.00 $ 92.60 Additional data concerning these products are listed below. Products A B C D Grinding minutes per unit 4.10 5.60 4.60 3.70 Selling price per unit $ 76.40 $ 93.80 $ 87.70 $ 104.50 Variable selling cost per unit $ 2.50 $ 1.50 $ 3.60 $ 1.90 Monthly demand in units 4,300 4,300 3,300 2,300 The grinding machines are potentially the constraint in the production facility. A total of 53,900 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