Unaizah College of Engineering
Introduction to Engineering Design-2
GE 213
Semester: 411
Assignment # 2
Chapter 1
Work by:
1- SALEH AL.OBAID
2- IBRAHIM AL.BASSAM
3- OMAR AL.BASSAM
Presented to: Dr. Hussain Sadiq
Table of Contents
1. Introduction……………………………………………………………………..…... 1
2. Work …………………………………....................................................................... 1
3. Molding the beaver of sales of two business……………………………………….. 2
3-1 Problem Definition…………………………………...………………………. 2
3-2 Assumptions...................................................................................................... 3
3-3 Heuristics........................................................................................................... 3
3-4 Modeling Steps and Mathematical Equations................................................... 3
3-5 Model Implementation……………………………………………………….
4
3-5-1 Information area………………………………………………….. 4
3-5-2 Data area......................................................................................... 4
3-5-3 Excel Model Formulas.................................................................... 4
3-5-4 Overall View of the Excel Model................................................... 6
3-6 Results and Discussion..................................................................................... 8
3-6-1 Answers of Questions A.................................................... 8
3-6-2 Answer of Question B....................................................... 8
3-6-3 Answer of Question II.a.................................................... 8
3-6-4 Answer of Question II.b.................................................... 9
4. Conclusions………………………………………………………………………… 9
5. References………....................................................................................................... 9
Appendix I: Team Meeting Minutes............................................................................... 10
Appendix II: Graphs………………………………………………………………….. 11
GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
1. Introduction:
This is the assignment in GE213 course on chapter one which is primarily
concerned about introducing models. Therefore, what is going to be discussed can
be represented in two main parts; firstly, it will discuss the some basic
terminologies from the first chapter. These terminologies will be used all
throughout this report from the problem definition to the result discussion and
evaluation; secondly, it will show an external problem, the heuristic and the
modeling of solving the problem. Later on, an external problem will be introduced
and solved according to a certain heuristic. Briefly, the external problem was
concerned about evaluating the visibility of a new planning to invest an extra
amount of money of an investor, by adding this amount of investment to either of
two businesses, one of them is purchasing used mobile phones , modifying and
selling them and the other is dealing in new mobiles. The bottom-line beyond the
problem is figuring out how to choose between two alternatives to get the most
preferable decision based on the Robustness and sensitivity of the results.
2) Work:
A-Useful heuristics found in this chapter:
1. When it is difficult to find a solution to a problem, then it would be helpful to
start asking easier questions.
2. Before doing the model, think of what idea is the model supposed to give.
3. Modeling cannot be only an equation that has some significance; it could be a
chart, a table, a diagram or anything else that represents a certain idea.
B- Three lessons learnt from the chapter:
1. Even though some problem solutions seem sometimes strong, they may be
weak under other circumstances.
2. Repeating the question “What is a Model?” whenever we try to build a model.
3. Some terminologies (like variables and parameters, Trade-offs and sensitivity
…etc) were useful to criticize our models.
C- Terminologies: [1]
Model:
It is diagram, table or equations that have a purposeful representation.
Trade-off:
It is a situation that involves losing one quality or aspect of something in return for
gaining another quality or aspect. It implies a decision to be made with full
comprehension of both the upside and downside of a particular choice.
Accuracy:
It is a term that shows how reliable any estimation of the input data and how much
the range of values of assumption is close to the best solution.
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
Variables and parameters:


Variables are the factors in the model that are actively changing.
Parameters also may be changed, but in the secondary sense of asking how a
change in parameters alter the relationship between the variable or (variables)
and answer the problem. Parameter that cannot be changed a called constant of
the model.
Robustness:
It is used to identify decisions made with a process that includes formal
consideration of uncertainty. A robust decision is the best possible choice, one found
by eliminating all the uncertainty possible within available resources, and then
choosing, with known and acceptable levels of satisfaction and risk.
Critique of model:
It is a list of point that display the good and bad qualities of model so that we build
our judgment on it.
Sensitivity:
It means how our decision of selecting a particular choice might be affected by
changes in variables or parameter.
3- Modeling the behavior of sales of two Business:
3-1 Problem Definition
We are an investor who has two businesses; the first is purchasing used mobile
phones, modifying and selling them. The second is dealing in new mobiles. The first
business has a long term profit cycle, however it has a profit margin ranges from 35
% to 60 % of the purchasing price. The second has a short term profit cycle and has
a profit margin ranges from 15 % to 35 % of the purchasing price. Now, We have
an extra amount of money, which is enough to be invested in only one of the two
businesses. By adding this amount of investment to either of the two businesses, its
sales are supposed to be doubled.
Given Data:
Establish a predictive model to find out, to which of the two businesses the new
investment is supposed to be added. Consider the following notes and directions:
a)
Sales records during the last three years give the following
monthly basis selling data: Selling prices of used mobile phones
vary between SR 300 and SR 2,000.
The number of sold used mobiles between 30 and 50.
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
Selling prices of new mobiles vary between SR
1,200 and SR 8,000. The number of new mobiles
between 15 and 30.
3-2Assumptions:
In the modeling process, one must assume things that are not known for sure, so we
will assume things in this assignment such as:
•purchasing used mobile phones has a profit margin ranges from 35 % to 60 % of the
purchasing price
•dealing in new mobiles has profit a margin ranges from 15 % to 35 % of the
purchasing price
• amount of investment to either of the two Business, its sales are supposed to be
doubled.
3-3 Heuristics
The methods that are used in this report to solve the real problem are the following
methods:
1- The profit of each Business is going to be calculated individually.
2- The average profit that comes is multiplied by the number of the items sold in
month so that we get the average profit that sells .
3- The total profit that the investor is going to get by the end of 3 years is the
summation of the profits of the two Business.
4- use figures to help us to solve the problem.
5- Creating algorithm of problem.
6- Use “Random between “tool.
3-4 Modeling Steps and Mathematical Equations:

The calculations that will be done to get answers to the questions of

the problem include finding:
o The best Profit Business .
The equations that will be used in the calculations are:
𝑇𝑜𝑡𝑎𝑙𝑠𝑎𝑙𝑒𝑠 = 𝑇𝑜𝑡𝑎𝑙𝑝𝑟𝑜𝑓𝑖𝑡 × 𝑁𝑝ℎ𝑜𝑛𝑒𝑠
𝑇𝑜𝑡𝑎𝑙𝑝𝑟𝑜𝑓𝑖𝑡 = 𝑇𝑜𝑡𝑎𝑙𝑠𝑎𝑙𝑒𝑠 − 𝐶
𝐶=
𝑇𝑜𝑡𝑎𝑙𝑠𝑎𝑙𝑒𝑠
𝐾
Where:

“𝑇𝑜𝑡𝑎𝑙𝑝𝑟𝑜𝑓𝑖𝑡 ” be the total profit in S.R .




“𝑇𝑜𝑡𝑎𝑙𝑠𝑎𝑙𝑒𝑠 ” the total Sales, SR
“𝐶”: Cost, SR
“𝑁𝑝ℎ𝑜𝑛𝑒𝑠 ” Number of phones
“𝐾” ∶ 𝑃𝑒𝑟𝑠𝑒𝑛𝑡 𝑝𝑟𝑜𝑓𝑖𝑡 ≤ 1
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
3-5 Model Implementation
In this part we show the process of our work. The sequence that begins with the
given information’s and leads the outcome results.
3-5-1 Information area
First thing we started with is the general information in the Figure 1.
Fig1. General information
3-5-2 Data area
The starting point to solve the problem is together the given data. They are shown
in Figure 2.
Fig.2 Data area
3-5-3 Excel Model Formulas
The equation of the Excel model in (show Formula) option as shown in Figures
3,4,5,6.
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
Fig.3 Equation used in the Excel Model
Fig.4 Equation used in the Excel Model cont.
5
GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
Fig.5 Equation used in the Excel Model cont.
Fig.6 Equation used in the Excel Model cont.
3-5-4 Overall View of the Excel Model
Here is a general over view on the work on the Excel assignment in Figure 7 .
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
Fig.7 Excel over view
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
3-6 Results and Discussion:
This section explains the results obtained from the constructed model and the answers
to the external problem questions.
3-6-1. Answer of Question: A
We gave random values for sales of used mobile and new mobile for 36 months to
know the profits tend to any of them, and we can see the random in Figure (8).
Figure 8: Relationship Between used mobile Profits and new mobile Profits in case 1
3-6-2 Answer of Question: B:
As we see in Figure (8), the Sensitivity is low and robustness is medium, because
most random values tend to Mobiles.
3-6-3 Answer of Question: II.a
After we added the investment for the two businesses, we found total profits tend to
Mobiles profit. See Figure (9)
Figure 9: Relationship Between used mobile Profits and new mobile Profits in case 2
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
3-6-4 Answer of Question: II. b
As we see in Figure (9), the Sensitivity is low and robustness is medium, because
most random values tend to Mobiles.
4. Conclusions
Here we come to the end of this Seconded assignment report. This assignment is
aimed to introduce some terminologies about models, which is very important to
comprehend before building any model. The main topic in this report that we dealt
with trading-off two decisions about attaining more profits. And we use an Excel
program to find the answer for an external problem, which is (choose between two
businesses). Therefore, in the work we tried to make a chart in which we can notice
the different change of profit for various input data. In short, we think that our work is
an excellent modeling that can be applied in the real life.
5. References
1. A. M. Starfield, Karl A. Smith , A. L. Bleloch, How to Model It: Problem
Solving for the Computer Age, 5th edition, Burgess International Group Inc |
April 1994|.
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
Third Meeting
One of the important things for any tasks for any team is meeting. Our team did tenth
meeting on Sunday 13/10/2019. In this meeting we done the assignment (2),
Agenda
Time
Waiting for members to coming
15 min
Complete the assignment (2)
3 hours
Conclusion:
Finally, finished the third meeting with 3 of the members and completed the
assignment (2) .







Time of meeting: 5:30 pm.
Duration of the meeting: 3:15 hours.
Place of meeting: The Fourth Cup Coffee.
Members:
Saleh Al.Obaid
Ibrahim Al.Bassam
Omer Al.Bassam
1
2
3
10
GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
Appendix II: Graphs
App 1: Relationship Between case 1
App 3: Relationship Between case 1
App 5: Relationship Between case 1
App 2: Relationship Between case 2
App 4: Relationship Between case 2
App 6: Relationship Between case 2
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GE 213, Semester 411
13/10/2019
Group#1 -Team #5:
Ibrahim, Omar, Saleh
Assignment No. 2: Introduction to Excel Modeling
App 7: Relationship Between case 1
App 8: Relationship Between case 2
App 9: Relationship Between case 1
App 11: Relationship Between case 1
App 13: Relationship Between case 1
App 10: Relationship Between case 2
App 12: Relationship Between case 2
App 14: Relationship Between case 2
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