Solver for optimization in Excel - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the Solver tool in Excel?

Solver helps find the best solution by changing values in cells to maximize, minimize, or reach a specific target for a formula.

beginner

Which three main parts do you need to set up in Solver?

1. Objective cell (the formula to optimize)
2. Variable cells (cells Solver can change)
3. Constraints (rules Solver must follow)

beginner

What types of optimization goals can you choose in Solver?

You can choose to:
- Maximize the objective cell
- Minimize the objective cell
- Set the objective cell to a specific value

beginner

Why do you add constraints in Solver?

Constraints limit the values Solver can use, like keeping numbers positive or within a range, to make sure the solution is realistic.

beginner

How do you start Solver in Excel if you don’t see it in the Data tab?

You need to add it by going to File > Options > Add-ins > Manage Excel Add-ins > Go, then check Solver Add-in and click OK.

What does the 'Set Objective' field in Solver represent?

A The cell with the formula you want to optimize

B The cells Solver can change

C The limits for the variables

D The result of the Solver process

The 'Set Objective' is the cell containing the formula you want to maximize, minimize, or set to a value.

Which of these is NOT a type of constraint you can add in Solver?

A Cell value must be greater than or equal to a number

B Cell value must be text

C Cell value must be less than or equal to a number

D Cell value must be an integer

Solver constraints work with numbers and ranges, not text values.

If you want Solver to find the smallest possible value for your formula, which option do you choose?

A None

B Max

C Value Of

D Min

Choosing 'Min' tells Solver to minimize the objective cell's value.

What happens if Solver cannot find a solution that meets all constraints?

A It shows an error message

B It gives the closest possible solution

C It ignores constraints

D It crashes Excel

Solver will notify you if no solution meets all constraints.

How do you tell Solver which cells it can change?

A By setting the objective cell

B By adding constraints

C By selecting the variable cells

D By formatting the cells

Variable cells are the cells Solver changes to optimize the objective.

Explain how you would set up Solver to maximize profit in a sales spreadsheet.

Think about what you want to change, what you want to improve, and what rules must be followed.

Describe the role of constraints in Solver and give two examples.

Constraints keep the solution realistic and practical.

Practice

1. What is the main purpose of Excel's Solver tool?

easy

A. To format cells with colors

B. To create charts and graphs automatically

C. To sort data alphabetically

D. To find the best values for variables to achieve a goal

Solution

1. Step 1: Understand Solver's function

   Solver is designed to adjust variables to optimize a target value.

2. Step 2: Compare options

   Only To find the best values for variables to achieve a goal describes finding best values to reach a goal, which matches Solver's purpose.

3. Final Answer:

   To find the best values for variables to achieve a goal -> Option D

4. Quick Check:

   Solver = optimization tool [OK]

Hint: Solver finds best numbers to reach your goal [OK]

Common Mistakes:

• Confusing Solver with chart tools
• Thinking Solver sorts or formats data
• Assuming Solver only works with text

2. Which of these is the correct way to set the objective cell in Solver?

easy

A. Select any empty cell

B. Select the cell with the formula you want to optimize

C. Select the entire worksheet

D. Select only cells with text

Solution

1. Step 1: Identify the objective cell role

   The objective cell contains the formula Solver tries to maximize, minimize, or set to a value.

2. Step 2: Evaluate options

   Only Select the cell with the formula you want to optimize correctly states selecting the formula cell to optimize.

3. Final Answer:

   Select the cell with the formula you want to optimize -> Option B

4. Quick Check:

   Objective cell = formula cell [OK]

Hint: Objective cell must have the formula to optimize [OK]

Common Mistakes:

• Choosing empty cells without formulas
• Selecting too many cells
• Picking cells with only text

3. Given this setup: Objective cell B5 = SUM(B1:B4), variable cells B1:B4, and constraint B1>=0, what will Solver do if you set objective to maximize B5?

medium

A. Return an error because constraints are invalid

B. Decrease values in B1:B4 to minimize the sum

C. Increase values in B1:B4 to maximize the sum

D. Ignore constraints and set B1:B4 to zero

Solution

1. Step 1: Understand objective and variables

   The objective is to maximize the sum in B5, which depends on B1:B4 values.

2. Step 2: Apply constraints

   Constraint B1>=0 means B1 cannot be negative, but no upper limit is set.

3. Step 3: Predict Solver behavior

   Solver will increase B1:B4 values (within constraints) to maximize the sum.

4. Final Answer:

   Increase values in B1:B4 to maximize the sum -> Option C

5. Quick Check:

   Maximize sum = increase variables [OK]

Hint: Maximize sum by increasing variable cells [OK]

Common Mistakes:

• Thinking Solver minimizes when set to maximize
• Ignoring constraints
• Assuming Solver returns errors without reason

4. You set Solver to minimize cell C10 by changing C1:C5 but get an error saying 'No feasible solution found'. What is a likely cause?

medium

A. Constraints are too strict or conflicting

B. Objective cell has no formula

C. Variable cells contain text instead of numbers

D. Solver add-in is not installed

Solution

1. Step 1: Understand 'No feasible solution' error

   This error means Solver cannot find values meeting all constraints.

2. Step 2: Analyze possible causes

   Too strict or conflicting constraints often cause no solution.

3. Step 3: Evaluate other options

   Objective cell without formula or text in variables cause different errors; Solver add-in missing prevents running Solver.

4. Final Answer:

   Constraints are too strict or conflicting -> Option A

5. Quick Check:

   No feasible solution = conflicting constraints [OK]

Hint: Check constraints if Solver finds no solution [OK]

Common Mistakes:

• Ignoring constraint conflicts
• Assuming Solver add-in missing causes this error
• Not verifying variable cell data types

5. You want to minimize total cost in cell D10 by changing quantities in D1:D5. Each quantity must be an integer between 1 and 10. How do you set up Solver correctly?

hard

A. Set objective to minimize D10, variable cells D1:D5, add constraints D1:D5 >=1, D1:D5 <=10, and select 'Make Integer' for D1:D5

B. Set objective to maximize D10, variable cells D1:D5, no constraints needed

C. Set objective to minimize D10, variable cells D1:D5, add constraint D1:D5 = 5 only

D. Set objective to minimize D10, variable cells D1:D5, add constraint D1:D5 text only

Solution

1. Step 1: Define objective and variables

   Objective is to minimize D10 by changing D1:D5 quantities.

2. Step 2: Add constraints for integer and range

   Quantities must be integers between 1 and 10, so add constraints D1:D5 >=1, D1:D5 <=10, and set 'Make Integer' for D1:D5.

3. Step 3: Evaluate options

   Only Set objective to minimize D10, variable cells D1:D5, add constraints D1:D5 >=1, D1:D5 <=10, and select 'Make Integer' for D1:D5 correctly sets objective, variables, and all constraints including integer requirement.

4. Final Answer:

   Set objective to minimize D10, variable cells D1:D5, add constraints D1:D5 >=1, D1:D5 <=10, and select 'Make Integer' for D1:D5 -> Option A

5. Quick Check:

   Integer constraints + bounds = correct setup [OK]

Hint: Add integer and range constraints for quantities [OK]

Common Mistakes:

• Forgetting to set integer constraint
• Using maximize instead of minimize
• Setting wrong or missing constraints