Exam 3: Modeling and Solving Lp Problems in a Spreadsheet

A financial planner wants to design a portfolio of investments for a client. The client has $400,000 to invest and the planner has identified four investment options for the money. The following requirements have been placed on the planner. No more than 30% of the money in any one investment, at least one half should be invested in long-term bonds which mature in six or more years, and no more than 40% of the total money should be invested in B or C since they are riskier investments. The planner has developed the following LP model based on the data in this table and the requirements of the client. The objective is to maximize the total return of the portfolio. ​ Formulate the LP for this problem.

Exhibit 3.2 The following questions are based on this problem and accompanying Excel windows. The Byte computer company produces two models of computers, Plain and Fancy. It wants to plan how many computers to produce next month to maximize profits. Producing these computers requires wiring, assembly and inspection time. Each computer produces a certain level of profits but faces only a limited demand. There are also a limited number of wiring, assembly and inspection hours available in each month. The data for this problem is summarized in the following table. -Refer to Exhibit 3.2. Which cells should be the constraint cells in this problem?

You have been given the following linear programming model and Excel spreadsheet to solve this problem. What cell references would you enter in the Analytic Solver Platform (ASP) task pane for the following? Objective Cell: Variables Cells: Constraints Cells: ​ ​ ​

Which of the following describes Data Envelopment Analysis (DEA).

A company needs to purchase several new machines to meet its future production needs. It can purchase three different types of machines A, B, and C. Each machine A costs $80,000 and requires 2,000 square feet of floor space. Each machine B costs $50,000 and requires 3,000 square feet of floor space. Each machine C costs $40,000 and requires 5,000 square feet of floor space. The machines can produce 200, 250 and 350 units per day respectively. The plant can only afford $500,000 for all the machines and has at most 20,000 square feet of room for the machines. The company wants to buy as many machines as possible to maximize daily production. What are the key formulas in cells G4 and E7 for this Excel spreadsheet implementation of the following formulation? ​ ​ ​

​Excel and other spreadsheets contain an add-on called solver.

A paper mill has received an order for rolls of paper. The customer wants 400 12" wide rolls, 300 18" rolls and 200 24" rolls. The company has 40" wide rolls of paper which it can slit to the appropriate width. The company wants to minimize the number of rolls it must use to fill the order. ​ Formulate the LP for this problem.

Analytic Solver Platform (ASP) is ​functionally similar to Excel Solver but it offers many useful extensions.

Exhibit 3.1 The following questions are based on this problem and accompanying Excel windows. Jones Furniture Company produces beds and desks for college students. The production process requires carpentry and varnishing. Each bed requires 6 hours of carpentry and 4 hour of varnishing. Each desk requires 4 hours of carpentry and 8 hours of varnishing. There are 36 hours of carpentry time and 40 hours of varnishing time available. Beds generate $30 of profit and desks generate $40 of profit. Demand for desks is limited, so at most 8 will be produced. The LP model for the problem is -Refer to Exhibit 3.1. Which cells should be the constraint cells in this problem?

You have been given the following linear programming model and Excel spreadsheet to solve this problem. What formulas should be entered into cells E5 and D8:D10 to implement this model? ​ ​

Exhibit 3.3 The following questions are based on this problem and accompanying Excel windows. Jack's distillery blends scotches for local bars and saloons. One of his customers has requested a special blend of scotch targeted as a bar scotch. The customer wants the blend to involve two scotch products, call them A and B. Product A is a higher quality scotch while product B is a cheaper brand. The customer wants to make the claim the blend is closer to high quality than the alternative. The customer wants 50 1500 ml bottles of the blend. Each bottle must contain at least 48% of Product A and at least 500 ml of B. The customer also specified that the blend have an alcohol content of at least 85%. Product A contains 95% alcohol while product B contains 78%. The blend is sold for $12.50 per bottle. Product A costs $7 per liter and product B costs $3 per liter. The company wants to determine the blend that will meet the customer's requirements and maximize profit. -Refer to Exhibit 3.3. What formula should be entered in cell E5 in the accompanying Excel spreadsheet to compute total cost?

Exhibit 3.4 The following questions are based on this problem and accompanying Excel windows. A financial planner wants to design a portfolio of investments for a client. The client has $300,000 to invest and the planner has identified four investment options for the money. The following requirements have been placed on the planner. No more than 25% of the money in any one investment, at least one third should be invested in long-term bonds which mature in seven or more years, and no more than 25% of the total money should be invested in C or D since they are riskier investments. The planner has developed the following LP model based on the data in this table and the requirements of the client. The objective is to maximize the total return of the portfolio. -Refer to Exhibit 3.4. What formula should be entered in cell B7 in the accompanying Excel spreadsheet to compute total dollars invested?

Exhibit 3.3 The following questions are based on this problem and accompanying Excel windows. Jack's distillery blends scotches for local bars and saloons. One of his customers has requested a special blend of scotch targeted as a bar scotch. The customer wants the blend to involve two scotch products, call them A and B. Product A is a higher quality scotch while product B is a cheaper brand. The customer wants to make the claim the blend is closer to high quality than the alternative. The customer wants 50 1500 ml bottles of the blend. Each bottle must contain at least 48% of Product A and at least 500 ml of B. The customer also specified that the blend have an alcohol content of at least 85%. Product A contains 95% alcohol while product B contains 78%. The blend is sold for $12.50 per bottle. Product A costs $7 per liter and product B costs $3 per liter. The company wants to determine the blend that will meet the customer's requirements and maximize profit. -Refer to Exhibit 3.3. Which of the following statements could represent a constraint in this problem?

Microsoft Excel contains a built-in optimizer called

Exhibit 3.5 The following questions are based on this problem and accompanying Excel windows. A company is planning production for the next 4 quarters. They want to minimize the cost of production. The production cost is stable but demand and production capacity vary from quarter to quarter. The maximum amount of inventory which can be held is 12,000 units and management wants to keep at least 3,000 units on hand. Quarterly inventory holding cost is 3% of the cost of production. The company estimates the number of units carried in inventory each month by averaging the beginning and ending inventory for each month. There are currently 5,000 units in inventory. The company wants to produce at no less than one half of its maximum capacity in any quarter. -Refer to Exhibit 3.5. What formula could be entered in cell F20 in the accompanying Excel spreadsheet to compute the Total Cost for all four quarters?

The hospital administrators at New Hope, County General, and City East recently received notice of an impending state inspection of their facilities. Under new guidelines established to improve the overall health care system, state inspectors will be assessing the efficiency of each hospital. The staff at New Hope has suggested a mutual assistance program in preparation for the inspections and have proposed using DEA as a means to assess the efficiency of each facility. The data collected thus far is summarized in the following table. All data reflects averages compiled over the past six months. What are the key formulas in cells I4, J4, K4, B11 and B12 for this Excel spreadsheet implementation of the following formulation? ​ ​ ​

Exhibit 3.1 The following questions are based on this problem and accompanying Excel windows. Jones Furniture Company produces beds and desks for college students. The production process requires carpentry and varnishing. Each bed requires 6 hours of carpentry and 4 hour of varnishing. Each desk requires 4 hours of carpentry and 8 hours of varnishing. There are 36 hours of carpentry time and 40 hours of varnishing time available. Beds generate $30 of profit and desks generate $40 of profit. Demand for desks is limited, so at most 8 will be produced. The LP model for the problem is -Refer to Exhibit 3.1. Which cells should be changing cells in this problem?

Which type of spreadsheet cell represents the objective function in an LP model?

Exhibit 3.5 The following questions are based on this problem and accompanying Excel windows. A company is planning production for the next 4 quarters. They want to minimize the cost of production. The production cost is stable but demand and production capacity vary from quarter to quarter. The maximum amount of inventory which can be held is 12,000 units and management wants to keep at least 3,000 units on hand. Quarterly inventory holding cost is 3% of the cost of production. The company estimates the number of units carried in inventory each month by averaging the beginning and ending inventory for each month. There are currently 5,000 units in inventory. The company wants to produce at no less than one half of its maximum capacity in any quarter. -Refer to Exhibit 3.5. What formula should be entered in cell C6 in the accompanying Excel spreadsheet to compute ending inventory?

A farmer is planning his spring planting. He has 20 acres on which he can plant a combination of Corn, Pumpkins and Beans. He wants to maximize his profit but there is a limited demand for each crop. Each crop also requires fertilizer and irrigation water which are in short supply. The following table summarizes the data for the problem. What are the key formulas in cells F5 and E8 for this Excel spreadsheet implementation of the following formulation? ​