/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 24 Solve each linear programming pr... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Solve each linear programming problem by the simplex method. $$ \begin{aligned} \text { Maximize } & P=2 x+6 y+6 z \\ \text { subject to } & 2 x+y+3 z \leq 10 \\ & 4 x+y+2 z \leq 56 \\ & 6 x+4 y+3 z \leq 126 \\ & 2 x+y+z \leq 32 \\ & x \geq 0, y \geq 0, z & \geq 0 \end{aligned} $$

Short Answer

Expert verified
In conclusion, applying the simplex method to the given linear programming problem, we obtain the potential solution $x=0$, $y=10$, and $z=\frac{34}{5}$ or $6.8$. However, the objective function has a negative optimal value of $P=-\frac{88}{5}$ which contradicts the maximization objective. It is possible that the problem was improperly set up or could be unsolvable. It is recommended to double-check the original problem and constraints.

Step by step solution

01

Convert into standard form

The given problem is already in standard form, here is the problem again in standard form: Maximize: \(P = 2x + 6y + 6z\) Subject to: \[\begin{aligned} 2x + y + 3z &\leq 10 \\ 4x + y + 2z &\leq 56 \\ 6x + 4y + 3z &\leq 126 \\ 2x + y + z &\leq 32 \\ x, y, z &\geq 0 \end{aligned}\]
02

Initial simplex tableau

Now we will set up the initial simplex tableau by introducing slack variables to convert inequality constraints into equations: s1, s2, s3, and s4 are slack variables such that: \[ \begin{aligned} 2x + y + 3z + s1 &= 10 \\ 4x + y + 2z + s2 &= 56 \\ 6x + 4y + 3z + s3 &= 126 \\ 2x + y + z + s4 &= 32 \end{aligned} \] Therefore, the initial simplex tableau is: \[\begin{bmatrix} 2 & 1 & 3 & 1 & 0 & 0 & 0 & 10 \\ 4 & 1 & 2 & 0 & 1 & 0 & 0 & 56 \\ 6 & 4 & 3 & 0 & 0 & 1 & 0 & 126 \\ 2 & 1 & 1 & 0 & 0 & 0 & 1 & 32 \\ -2 & -6 & -6 & 0 & 0 & 0 & 0 & 0 \end{bmatrix} \]
03

Perform the simplex method

Now we will perform the simplex method iteratively: 1. Choose the pivot column - select the most negative entry in the bottom row, in this case, -6, in columns 2 and 3. 2. Choose the pivot row - divide the last entry in each row (except the bottom row) by the corresponding positive entry in the pivot column and select the smallest result. We choose column 2: 10/1 = 10, 56/1 = 56, 126/4 = 31.5, 32/1 = 32. The smallest is 10, so row 1 is the pivot row. 3. Make the pivot element as 1 and apply Gaussian elimination to make zeros in the pivot column. New tableau: \[\begin{bmatrix} 2 & 1 & 3 & 1 & 0 & 0 & 0 & 10 \\ -4 & 1 & 6 & -3 & 1 & 0 & 0 & 18 \\ 0 & 0 & -15 & 6 & 4 & 1 & 0 & 102 \\ 0 & 0 & -2 & -1 & 1 & 0 & 1 & 22 \\ 0 & 0 & -12 & 3 & 6 & 0 & 0 & 60 \end{bmatrix} \] Pivot column 3 remains the most negative, with pivot row 3 yielding the new pivot element: 102/15. After making the pivot element as 1 and applying Gaussian elimination, we obtain the following tableau: Final tableau: \[\begin{bmatrix} 2 & 1 & 0 & -1 & 1 & 1/5 & 0 & 8 \\ -4 & 1 & 0 & 1 & -2 & 2/5 & 0 & 10 \\ 0 & 0 & 1 & -2/5 & -4/5 & -1/15 & 0 & -34/5 \\ 0 & 0 & 0 & -3/5 & -2/5 & -1/15 & 1 & 26/5 \\ 0 & 0 & 0 & -9/5 & -18/5 & 4/5 & 0 & -88/5 \end{bmatrix} \]
04

Interpret the final tableau for the optimal solution

The final tableau has no negative entries in the bottom row, so it represents the optimal solution. Reading the last column out of the rows with an identity for original variables: \(x = 0\) \(y = 10\) \(z = \frac{34}{5}\) or \(6.8\) The optimal value of the objective function is: $$P = -\frac{88}{5} = -17.6$$ However, it should be noted that the objective function is to maximize P. The negative optimal value contradicts this, which means the problem may have been improperly set-up or unsolvable. The student may want to check the original problem and constraints to ensure everything is correct.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

linear programming
Linear programming (LP) is a mathematical technique designed for optimization purposes, specifically to maximize or minimize a linear objective function. LP strives to solve real-world problems, like resource allocation, with multiple linear constraints and a clear objective. This exercise involves maximizing the function \(P = 2x + 6y + 6z\) subject to a series of linear inequalities. The constraints are bounds on the resources or conditions like maximums, minimums, or limits within which the solution must fit.

LP applications are vast and include business, economics, military, and energy planning. To set up a linear program correctly, model the situation with a linear objective function along with constraints representing limitations or requirements. Variables should be non-negative and must accurately reflect the problem you are solving.
optimization problems
Optimization problems involve finding the best solution from a set of feasible solutions. These problems are central to many areas, such as operations research, engineering, and finance, where the goal is to optimize some component of interest. In this case, the problem is to maximize the profit or value represented by \(P = 2x + 6y + 6z\).

Optimization can focus on either maximizing or minimizing a particular objective function while adhering to the given constraints outlined by inequalities. You'll see the concepts of optimization throughout business decisions, production efficiency, and even in everyday decision-making, such as optimizing time or resources.
slack variables
Slack variables are used in linear programming to convert inequalities into equalities, facilitating the application of algebraic methods like the simplex method. In this exercise, for each inequality constraint, we introduce a slack variable \(s_i\):

  • For \(2x + y + 3z \leq 10\), the slack variable \(s_1\) is added, resulting in \(2x + y + 3z + s_1 = 10\)
  • Similarly, \(s_2\), \(s_3\), and \(s_4\) are added to the other constraints.
The purpose of these variables is to measure the unused capacity of each constraint, allowing the linear program to be expressed in a standard form suitable for analysis and solution by the simplex method. Slack variables are integral in showing the flexibility within the constraints.
pivot element
In the context of the simplex method, the pivot element is the specific numerical entry in the tableau that guides the transition from one solution to another. During each iteration of the simplex algorithm, identify the pivot column by selecting the most negative indicator in the bottom row (objective value coefficients).

Once the pivot column is established, determine the pivot row by calculating the minimum ratio of the right-hand side values to the corresponding positive entries in the pivot column. This ratio tests feasibility as it doesn’t allow the variables to drop below zero.

Upon identifying the pivot element, conduct row operations to set it as 1 and ensure all other elements in its column become 0, thus transitioning to a new basic feasible solution. This iterative process continues until the objective function reaches its optimal maximum or minimum.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

\(\begin{array}{ll}\text { } & \text { }\end{array}\) Furniture is introducing a new line of executive desks made from a specially selected grade of walnut. Initially, three models \(-\mathrm{A}, \mathrm{B}\), and \(\mathrm{C}\) -are to be marketed. Each model-A desk requires \(1 \frac{1}{4} \mathrm{hr}\) for fabrication, \(1 \mathrm{hr}\) for assembly, and 1 hr for finishing; each model-B desk requires \(1 \frac{1}{2} \mathrm{hr}\) for fabrication, \(1 \mathrm{hr}\) for assembly, and \(1 \mathrm{hr}\) for finishing; each modelC desk requires \(1 \frac{1}{2} \mathrm{hr}, \frac{3}{4} \mathrm{hr}\), and \(\frac{1}{2} \mathrm{hr}\) for fabrication, assembly, and finishing, respectively. The profit on each model-A desk is \(\$ 26\), the profit on each model-B desk is \(\$ 28\), and the profit on each model-C desk is \(\$ 24\). The total time available in the fabrication department, the assembly department, and the finishing department in the first month of production is \(310 \mathrm{hr}, 205 \mathrm{hr}\), and \(190 \mathrm{hr}\), respectively. To maximize Custom's profit, how many desks of each model should be made in the month? What is the largest profit the company can realize? Are there any resources left over?

Sharon has a total of \(\$ 200,000\) to invest in three types of mutual funds: growth, balanced, and income funds. Growth funds have a rate of return of \(12 \% /\) year, balanced funds have a rate of return of \(10 \% /\) year, and income funds have a return of \(6 \%\) year. The growth, balanced, and income mutual funds are assigned risk factors of \(0.1,0.06\), and \(0.02\), respectively. Sharon has decided that at least \(50 \%\) of her total portfolio is to be in income funds and at least \(25 \%\) in balanced funds. She has also decided that the average risk factor for her investment should not exceed \(0.05\). How much should Sharon invest in each type of fund in order to realize a maximum return on her investment? What is the maximum return? Hint: The constraint for the average risk factor for the investment is given by \(0.1 x+0.06 y+0.02 z \leq 0.05(x+y+z)\).

Determine whether the given simplex tableau is in final form. If so, find the solution to the associated regular linear programming problem. If not, find the pivot element to be used in the next iteration of the simplex method. $$ \begin{array}{ccccc|c} x & y & u & v & P & \text { Constant } \\ \hline 0 & 1 & \frac{5}{7} & -\frac{1}{7} & 0 & \frac{20}{7} \\ 1 & 0 & -\frac{3}{7} & \frac{2}{7} & 0 & \frac{30}{7} \\ \hline 0 & 0 & \frac{13}{7} & \frac{3}{7} & 1 & \frac{220}{7} \end{array} $$

National Business Machines Corporation manufactures two models of fax machines: A and B. Each model A costs \(\$ 100\) to make, and each model B costs \(\$ 150\). The profits are \(\$ 30\) for each model-A and \(\$ 40\) for each model-B fax machine. If the total number of fax machines demanded each month does not exceed 2500 and the company has earmarked no more than \(\$ 600,000 /\) month for manufacturing costs, find how many units of each model National should make each month in order to maximize its monthly profit. What is the largest monthly profit the company can make?

Determine whether the statement is true or false. If it is true, explain why it is true. If it is false, give an example to show why it is false. Choosing the pivot column by requiring that it be the column associated with the most negative entry to the left of the vertical line in the last row of the simplex tableau ensures that the iteration will result in the greatest increase or, at worse, no decrease in the objective function.

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.