Post on 28-Mar-2015
transcript
Denise Sakai Troxell (2000)
Solving Equations
with Excel Solver
for Microsoft Excel 2000
Denise Sakai Troxell (2000)
A Simple Problemgrades, grades, grades*…
You would love to have a quiz average of 80 points (or better) in the QTM1300 course by the end of the semester.
Your quiz scores on the first eight quizzes are given in the table below.
Quiz 1 2 3 4 5 6 7 8
Score 90 88 78 68 84 82 66 74
What scores do you need to earn on the 9th and 10th final quizzes in order to meet your goal average of 80 points? * from FCL Excel Notes by Joyce Gordon, Babson College, 1998.
Denise Sakai Troxell (2000)
You are looking for
x = score on 9th quiz (0 x 100)
y = score on 10th quiz (0 y 100)
so that
Formulate the Problemobtain equation to be solved
90 + 88 + 78 + 68 + 84 + 82 + 66 + 74 + x + y = 80
10
Quiz AverageQuiz Average
NOTE: When using Excel Solver to solve an equation make sure the right-hand side is a constant.
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverstart with a blank sheet
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter labels and constants
Enter labels in cells A1:A13 and
B1
Enter labels in cells A1:A13 and
B1
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter labels and constants
NOTE: These labels are not essential for the use of
Solver
NOTE: These labels are not essential for the use of
Solver
Denise Sakai Troxell (2000)
enter labels and constantsPreparing the Worksheet for Solver
Enter constants in cells B2:B9
Enter constants in cells B2:B9
Remember…
7466828468788890Score
87654321Quiz
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter formula
Variable values in cells B10 and B11Variable values in cells B10 and B11
Left-hand side of equation in cell B13
Left-hand side of equation in cell B13
NOTE: These cells will be colored to indicate that they are essential for
Solver
NOTE: These cells will be colored to indicate that they are essential for
Solver
Remember…
90 + 88 + 78 + 68 + 84 + 82 + 66 + 74 + x + y = 80
10
xy
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter formula
Click on cell B13Click on cell B13
Remember…
90 + 88 + 78 + 68 + 84 + 82 + 66 + 74 + x + y = 80
10
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter formula
Type in =AVERAGE(Type in =AVERAGE(
Remember…
90 + 88 + 78 + 68 + 84 + 82 + 66 + 74 + x + y = 80
10
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter formula
Remember…
90 + 88 + 78 + 68 + 84 + 82 + 66 + 74 + x + y = 80
10
Highlight cells B2:B11
Highlight cells B2:B11
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter formula
Type in ) and hit Enter
Type in ) and hit Enter
Remember…
90 + 88 + 78 + 68 + 84 + 82 + 66 + 74 + x + y = 80
10
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter formula
NOTE: Alternative formula for cell B13: =(B2+ B3+ B4+ B5+ B6+ B7+ B8+ B9+ B10+ B11)/10NOTE: Alternative formula for cell B13: =(B2+ B3+ B4+ B5+ B6+ B7+ B8+ B9+ B10+ B11)/10
Denise Sakai Troxell (2000)
Preparing the Worksheet for Solverenter formula
NOTE: The function AVERAGE entered in cell B13 returns the average of the values in cells B2:B11;
blank cells are ignored
NOTE: The function AVERAGE entered in cell B13 returns the average of the values in cells B2:B11;
blank cells are ignored
Denise Sakai Troxell (2000)
Using Solverinvoke Solver
Click on ToolsClick on Tools
Denise Sakai Troxell (2000)
Using Solverinvoke Solver
Click on SolverClick on Solver
Denise Sakai Troxell (2000)
Using Solverinvoke Solver
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
Click on cell B13Click on cell B13
NOTE: The cell displayed in the Set Target Cell: box must contain the formula for the left-hand side of the equation
(cell B13)
NOTE: The cell displayed in the Set Target Cell: box must contain the formula for the left-hand side of the equation
(cell B13)
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
Check the Value of: circle
Check the Value of: circle
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
NOTE: The value displayed in the Value of: box must be the constant on the right-hand side of the
equation (80)
NOTE: The value displayed in the Value of: box must be the constant on the right-hand side of the
equation (80)
Click on the Value of: box
Click on the Value of: box
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
NOTE: The value displayed in the Value of: box must be the constant on the right-hand side of the
equation (80)
NOTE: The value displayed in the Value of: box must be the constant on the right-hand side of the
equation (80)
Type in 80Type in 80
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
Click on the By Changing Cells:
box
Click on the By Changing Cells:
box
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
Highlight cells B10:B11
Highlight cells B10:B11
NOTE: The cells displayed in the By Changing Cells: box must be the cells containing variable values
(cells B10:B11)
NOTE: The cells displayed in the By Changing Cells: box must be the cells containing variable values
(cells B10:B11)
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
Click on AddClick on Add
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
Highlight cells B10:B11
Highlight cells B10:B11
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
Click on the Cell Reference: box
Click on the Cell Reference: box
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
Make sure <= is displayed
Make sure <= is displayed
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
Click on the Constraint: box and type in 100
Click on the Constraint: box and type in 100
Denise Sakai Troxell (2000)
Using Solvercomplete the Solver Parameters dialog box
Click on OKClick on OK
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
NOTE: The Subject to the Constraints: box must contain the constraints on the variable values (x,y
100)
Denise Sakai Troxell (2000)
Using Solverset the Options
Click on OptionsClick on Options
Denise Sakai Troxell (2000)
Using Solverset the Options
Check the Assume Linear Model
and the Assume Non-
Negative boxes
Check the Assume Linear Model
and the Assume Non-
Negative boxes
NOTE: The equation (in the Target Cell B13) is linear on the non-negative variables (x in B10
and y in B11)
NOTE: The equation (in the Target Cell B13) is linear on the non-negative variables (x in B10
and y in B11)
Denise Sakai Troxell (2000)
Using Solverset the Options
Accept the remaining default options by clicking
on OK
Accept the remaining default options by clicking
on OK
NOTE: The equation (in the Target Cell B13) is linear on the non-negative variables (x in B10
and y in B11)
NOTE: The equation (in the Target Cell B13) is linear on the non-negative variables (x in B10
and y in B11)
Denise Sakai Troxell (2000)
Using Solverexecute Solver
Click on SolveClick on Solve
Denise Sakai Troxell (2000)
Using Solverread solution
You need to earn a score of 100 on the 9th quiz and 70 on the 10th quiz to meet your goal average of 80 points.
You need to earn a score of 100 on the 9th quiz and 70 on the 10th quiz to meet your goal average of 80 points.
Denise Sakai Troxell (2000)
Using Solverend execution
Click on OKClick on OK
Denise Sakai Troxell (2000)
Using Solvera final comment
NOTE: Excel Solver might not find all possible solutions
NOTE: Excel Solver might not find all possible solutions
You need algebra!
COMPLETE SOLUTION
You need to earn a score of
x on the 9th quiz,
where 70 x 100, and
170 – x on the 10th quiz
to meet your goal average of 80 points.
COMPLETE SOLUTION
You need to earn a score of
x on the 9th quiz,
where 70 x 100, and
170 – x on the 10th quiz
to meet your goal average of 80 points.