Chapter 6(D)

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Sensitivity
Output from Computer Solution : Changing Cells
Adjustable Cells
Cell
Name
$B$9 Solution Product1
$C$9 Solution Product2
Final Reduced Objective Allowable Allowable
Value
Cost
Coefficient Increase Decrease
2
0
3
4.5
3
6
0
5
1E+30
3
Final Value
The value of the variable in the optimal
solution
Reduced Cost
Increase in the objective function value per
unit increase in the value of a zero-valued
variable (a product that the model has
decided not to produce).
Allowable
Increase/
Decrease
Defines the range of the cost coefficients in
the objective function for which the current
solution (value of the variables in the optimal
solution) will not change.
Output from Computer Solution : Constraints
Constraints
Cell
Name
$D$5 Resource1 LHS
$D$6 Resource2 LHS
$D$7 Resource3 LHS
Final Shadow Constraint Allowable Allowable
Value
Price
R.H. Side
Increase Decrease
2
0
4
1E+30
2
12
1.5
12
6
6
18
1
18
6
6
Final Value
The usage of the resource in the optimal solution.
Shadow price
The change in the value of the objective function
per unit increase in the right hand side of the
constraint: Z = (Shadow Price)(RHS)
(Only for change is within the allowable range)
Output from Computer Solution : Constraints
Constraints
Cell
Name
$D$5 Resource1 LHS
$D$6 Resource2 LHS
$D$7 Resource3 LHS
Final Shadow Constraint Allowable Allowable
Value
Price
R.H. Side
Increase Decrease
2
0
4
1E+30
2
12
1.5
12
6
6
18
1
18
6
6
Constraint
R.H. Side
The current value of the right hand side of the
constraint (the amount of the resource that
is available).
Allowable
Increase/
Decrease
The range of values of the RHS for which
the shadow price is valid and hence for which
the new objective function value can be
calculated. (NOT the range for which the
current solution will not change.)
Net Profit product 1 = $7
Change the profit to 7, Solver again, Solve again
Adjustable Cells
Cell
Name
$B$9 Solution Product1
$C$9 Solution Product2
Final Reduced Objective Allowable Allowable
Value
Cost
Coefficient Increase Decrease
2
0
3
4.5
3
6
0
5
1E+30
3
Net Profit product 1 = $8
Change the profit to 8, Solver again, Solve again
Adjustable Cells
Cell
Name
$B$9 Solution Product1
$C$9 Solution Product2
Final Reduced Objective Allowable Allowable
Value
Cost
Coefficient Increase Decrease
2
0
3
4.5
3
6
0
5
1E+30
3
Problem Formulation
Given the following problem
Maximize Z = 3x1 + 5x2
Subject to: the following constraints
x1 + 3x2 ≤ 14
3x1 + 2x2 ≤ 15
x1, x2 ≥ 0
For the production combination of 3 units of product 1 and 3 units of product 2,
shadow price of which resource is equal to 0 ?
A)
Resource 1 (only)
B)
Resource 2 (only)
C)
both Resource 1 and Resource 2
D)
neither Resource 1 nor resource 2.
E)
can only be discovered by the sensitivity report
• Solve Windor Problem in excel
• Then discuss Sensitivity
Wyndor Optimal Solution
What is the optimal Objective function value for this problem?
What is the allowable range for changes in the objective coefficient for
Product 2
What is the allowable range for changes in the RHS for Resource 3.
If the coefficient of Product 2 in the objective function is changed to 7,
what will happen to the value of the objective function?
If the coefficient of Product 1 in the objective function is changed to 8,
what will happen to the value of the objective function?
If the RHS of Resource 2 is increased by 2 , what will happen to the
objective function.
If the RHS of Resource 1 is increased by 2, what will happen to the
objective function.
If the RHS of Resource 2 is decreased by 10, what will happen to the
objective function.
Wyndor Optimal Solution
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