These are questions from the textbook called Managerial desicion modeling. Chegg has a step by step explanation on how to do it but i dont understand it and need the assignment done.
A plumbing manufacturer makes two lines of bath- tubs, model A and model B. Every tub requires blending a certain amount of steel and zinc; the company has available a total of 24,500 pounds of steel and 6,000 pounds of zinc. Each model A bath- tub requires a mixture of 120 pounds of steel and 20 pounds of zinc, and each yields a profit of $90. Each model B tub produced can be sold for a profit of $70; it requires 100 pounds of steel and 30 pounds of zinc. To maintain an adequate supply of both models, the manufacturer would like the number of model A tubs made to be no more than 5 times the number of model B tubs. Find the best product mix of bathtubs.
A photocopy machine company produces three types of laser printers—the Print Jet, the Print Desk, and the Print Pro—the sale of which earn profits of $60, $90, and $73, respectively. The Print Jet requires 2.9 hours of assembly time and 1.4 hours of testing time. The Print Desk requires 3.7 hours of assem- bly time and 2.1 hours of testing time. The Print Pro requires 3 hours of assembly time and 1.7 hours of testing time. The company wants to ensure that Print Desk constitutes at least 15% of the total production and Print Jet and Print Desk together constitute at least 40% of the total production. There are 3,600 hours of assembly time and 2,000 hours of testing time available for the month. What combination of printers should be produced to maximize profits?