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Intro Mgmt Sci. 472.21 3 Fall 2011 Bruce Duggan. This week. work together on ch 2 & 3 problems particularly “model formulation” (math) dealing with ratios goal develop a standard “system” to attack each problem quiz Fri fair game all ch 2 problems probs 1 – 33 will only ask
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Intro Mgmt Sci 472.21 3 Fall 2011 Bruce Duggan
This week • work together on ch 2 & 3 problems • particularly • “model formulation” (math) • dealing with ratios • goal • develop a standard “system” to attack each problem • quiz Fri • fair game • all ch 2 problems • probs 1 – 33 • will only ask • write the linear program (the math)
St. A Craft League • Model formulation: • l.p. Max Z = $40x1 + $50x2 s.t. 1x1 + 2x2 40 4x1 + 3x2 120 x1, x2 0
Problems • review ch 2 problems • in group • 2 • 38 • yourself • 1 • 16
Remember St. Adolpe Craft League: We need a “standard” approach to produce a formula like this for each problem. Problems Max Z = $40x1 + $50x2 s.t. 1x1 + 2x2 40 4x1 + 3x2 120 x1, x2 0
Problems min or max? decision variables objective function constraints a “standard” approach
Problems min or max? decision variables outputs products some sort of result What are we trying to produce? how many of product 1? how many of product 2? how many of product…? a “standard” approach x1 x2 …xn
Problems min or max? decision variables objective function a “standard” approach Max Z = z1x1 + z2x2 +…znxn Min Z = z1x1 + z2x2 +…znxn
Problems min or max? decision variables objective function constraints inputs resources (max) requirements (min) a “standard” approach • non-negativity constraints • integer constraints • ratio requirements
Problems min or max? decision variables objective function constraints non-negative: integer constraint: a “standard” approach • max: a1x1 + a2x2 aavailable b1x1 + b2x2 bavailable … n1x1 + n2x2 navailable • min: xi0 a1x1 + a2x2 arequired b1x1 + b2x2 brequired … x?=0 or 1 n1x1 + n2x2 nrequired
Problems • 2: “A Company” • min or max? • max
Problems • 2: “A Company” • min or max? • decision variables • how many of product 1? • how many of product 2? x1 x2
Problems • 2: “A Company” • min or max? • decision variables • objective function Max Z = z1x1 + z2x2 Max Z = $6.00x1 + $4.00x2
Problems • 2: “A Company” • min or max? • decision variables • objective function • constraints • time available on line 1 • time available on line 2 a 100 hours b 42 hours 10x1 + 10x2100 hours a1x1 + a2x2 aavailable 7x1 + 3x242 hours b1x1 + b2x2 bavailable
Problems • 2: “A Company” Max Z = z1x1 + z2x2 Max Z = $6.00x1 + $4.00x2 s.t. a1x1 + a2x2 aavailable s.t. 10x1 + 10x2100 hours b1x1 + b2x2 bavailable 7x1 + 3x242 hours xi0 x1, x20
Problems • 38: “A Manufacturing Firm” • min or max? • decision variables • objective function • constraints
Problems • 38: “A Manufacturing Firm” • min or max? • max
Problems • 38: “A Manufacturing Firm” • min or max? • decision variables • how many of product 1? • how many of product 2? x1 x2
Problems • 38: “A Manufacturing Firm” • min or max? • decision variables • objective function Max Z = z1x1 + z2x2 Max Z = $30.00x1 + $70.00x2
Problems • 38: “A Manufacturing Firm” • min or max? • decision variables • objective function • constraints • assembly hours • finishing hours • warehouse space a 80 hours b 112 hours c space for 10 units
Problems • 38: “A Manufacturing Firm” Max Z = z1x1 + z2x2 Max Z = $30.00x1 + $70.00x2 s.t. a1x1 + a2x2 aavailable s.t. 4x1 + 10x280 hours b1x1 + b2x2 bavailable 14x1 + 8x2112 hours c1x1 + c2x2 cavailable x1 + x210 spaces xi0 x1, x20
Problems • 1: Marie baking for the PTA • min or max? • max
Problems • 1: Marie baking for the PTA • min or max? • decision variables • how many cakes? • how many loaves of bread? x1 x2
Problems • 1: Marie baking for the PTA • min or max? • decision variables • objective function Max Z = z1x1 + z2x2 Max Z = $10.00x1 + $6.00x2
Problems • 1: Marie baking for the PTA • min or max? • decision variables • objective function • constraints • cups of flour • cooking time a 20 cups b 180 minutes
Problems • 1: Marie baking for the PTA Max Z = z1x1 + z2x2 Max Z = $10.00x1 + $6.00x2 s.t. a1x1 + a2x2 aavailable s.t. 3x1 + 8x220 cups b1x1 + b2x2 bavailable 45x1 + 30x2180 min. x1, x20 and integer xi0 and integer
Problems • 16: “A Clothier” • min or max? • max
Problems • 16: “A Clothier” • min or max? • decision variables • how many coats? • how many pairs of slacks? x1 x2
Problems • 16: “A Clothier” • min or max? • decision variables • objective function Max Z = z1x1 + z2x2 Max Z = $50.00x1 + $40.00x2
Problems • 16: “A Clothier” • min or max? • decision variables • objective function • constraints • square yards of wool • hours of labour a 150 square yards b 200 hours
Problems • 16: “A Clothier” Max Z = z1x1 + z2x2 Max Z = $50.00x1 + $40.00x2 s.t. a1x1 + a2x2 aavailable s.t. 3x1 + 5x2150 sq. yards b1x1 + b2x2 bavailable 10x1 + 4x2200 hours x1, x20 and integer xi0 and integer
Problems min or max? decision variables objective function constraints inputs resources (max) requirements (min) a “standard” approach • non-negativity constraints • integer constraints • ratio requirements
Problems ratio requirements “no more than…” “at least…” “equal to…” must be referring to the decision variables the x’s the outputs a “standard” approach
Problems ratio requirements a “standard” approach write out a sentence for each requirement break apart if possible rewrite sentences using symbols: x = write ratios rearrange so that: unequal signs pointing same way as other constraints all on single line (no fractions) x’s on left side of equation x’s in order 0 on right side a “standard” approach
The Possibility Restaurant ratios at least 3 fish for every 2 beef at least 10% will order beef
The Possibility Restaurant ratios at least 3 fish for every 2 beef
The Possibility Restaurant ratios at least 10% beef
Let’s solve some problems • Xecko Tool • ch 3 pg 95 9th ed • Southern Sporting Goods • ch 3 prob 5-7 pg 96-97 • Food Max • ch 3 prob 40-41 pg 104 no graphs no “sensitivity analysis” yet not “standard form” yet formulas Excel
Xecko Tool • bidding on a job • manufacturing processes
Southern Sporting Goods • makes basketballs & footballs • manufacturing processes
Food Max • how much milk to stock
Your turn • Irwin Textile Mills • ch 3 prob 11-13 pg 98 • 12a, 12b, 12c • United Aluminium Company • ch 3 prob 14-16 pg 98-99 • 15a, 15b, 15c, 16c l.p. Excel no graph
Working On • Possibility Restaurant • pg 70 • don’t do “what if”s in last paragraph • Irwin Textile Mills • ch 3 prob 11-13 pg 98 • 12a, 12b, 12c • United Aluminium Company • ch 3 prob 14-16 pg 98-99 • 15a, 15b, 15c, 16c l.p. Excel no graph
The Possibility Restaurant But what about ratios?
To Do • Julia’s Food Booth • ch 3 case 3 pg 98-99 • A, B, C, D • Exeter Mines • ch 3 prob 48-49 pg 105 • 12a, 12b, 12c
Next Week • Sensitivity • Chapter 4 • more applications