DR. YANGA’S COLLEGES, INC.Wakas, Bocaue, Bulacan

College of Business AdministrationPreliminary Examination

Operations Research

NAME: ______________________________________________ DATE: ________________YEAR/SECTION: ______________________________________ SCORE: ________________

TRUE OR FALSE: Write on the blanks T for correct statement and F otherwise.

1. The cornerstone of Operations Research is mathematics. _______________2. A solution of the model is optimal if it satisfies all the constraints. _______________3. If available optimization algorithm is not applicable to a model, it may be useful to abandon

the search for optimal solution and settle for good solution using heuristics or rules of thumb.________________

4. Human elements do not affect most decision problems. _________________5. The problem definition phase is considered to be the most important phase of an OR study; it

gives direction and motivation to the OR team. _________________6. The non-negativity constraints are not always included in LP modeling. _________________7. A redundant constraint is a binding constraint. _________________8. The graph of minimization problem is usually unbounded.9. Conflicting constraints do not affect the feasibility of the solutions to an LP model. ________10. Sensitivity analysis is used to study the behavior of the LP model when changes are

introduced to the model. _______________.

LP MODEL DEVELOPMENT

1. Jerry must work at least 20 hrs a week to supplement his allowance while attending school. He has the opportunity to work in 2 stores: in store 1, Jerry can work between 5 to 12 hours. Both stores pay the same hourly wage. Jerry wants to base his decision on work stress factor. Based on interviews with present employees, Jerry estimates that on a scale of 1 to 10, the stress factors are 8 and 6 at stores 1 and 2 respectively. Because stress increases by the hour, he presumes that stress is proportional to the number of hours worked in the store. How many hours should Jerry work at each store?

Develop an LP model for the above problem in its complete form.

2. Dimensions Inc. makes two products: tables and chairs, which must be processed through assembly and finishing department. Assembly has 60 hours available at assembly while finishing can have as much as 48 hours to work. Manufacturing table needs 4 hours in assembly and 2 hours in finishing while making a chair requires 2 hours in assembly and 4 hours in finishing. If profit is $ 8 per table and $ 6 per chair. Develop a complete LP model.

GRAPHICAL ANALYSIS

The graph below presents the constraint functions of a given LP model plotted as straight lines. The objective function is indicated in the graph. You are required to:

a. Identify the feasible solution by shading the appropriate area.b. Identify and label the corner points.c. Compute the objective function for each of the corner points.d. Choose the optimal solution.

Prepared by: ELENITA A. DELA CRUZ Instructor

Reviewed by: PROF. AZENITH H CASTILLO PROF. MICHAEL S. YANGA Program Head Dean

Recommending approval: PROF. PERLA B. MORAÑO

Director, CCDIT

Approved by: PROF. EDGAR S YANGA VPAA