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OR Case Study Analysis

-By

Aditya Karam( 04), Gurjinder Singh(10), Deepti

Sana(40), Kaushik Mandal(41), Pankaj Bajaj(59)

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CASE 4.2 NEW FRONTIERS

A Summary

Rob Richman, president of AmeriBank is bothered about the state of his bank.

AmeriBank, a medium-sized bank with branches throughout the United States, is

headed for dire economic straits. The bank is simply losing customers to nonbank

and foreign bank competitors. Many American banks have been suffering

significant losses because of increasing competition from nonbank and foreign

bank competitors offering services typically in the domain of American banks.

Rob has one strategy for distinguishing AmeriBank from its competitors is to

improve services that nonbank and foreign bank competitors do not readily

provide transaction services. Internet allows this convenient transaction method.

Over the Internet, customers are able to perform transactions on their desktop

computers either at home or at work.

Rob needs to understand the market for Web banking and the services

AmeriBank should provide over the Internet. Like balance inquiries, transactions,

limitations, recapture a portion of the investment market by continuously running

stock prices and allowing customers to make stock transactions over the Internet

for a minimal fee.

Rob has decided to outsource the survey project to a professional survey

company. He has opened the project up for bidding by several survey companies

and will award the project to the company which is willing to perform the survey

for the least cost.

Sophisticated Surveys is one of three survey companies competing for the project.

Rob provided each survey company with a list of survey requirements to ensure

that

AmeriBank receives the needed information for planning the Web banking

project.

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He tries to acquire information about the age groups of account holders, their

internet usage ability, income levels, and investment behavior. AmeriBank wants

to interview 2,000 customers with at least 20 percent from the first age group, at

least 27.5 percent from the second age group, at least 15 percent from the thirdage group, and at least 15 percent from the fourth age group. Rob wants to

ensure that the survey includes a mix of customers who know the Internet well

and those that have less exposure to the Internet. To ensure that AmeriBank

obtains the correct mix, he wants to interview at least 15 percent of customers

from the Silicon Valley where Internet use is high, at least 35 percent of

customers from big cities where Internet use is medium, and at least 20 percent

of customers from small towns where Internet use is low.

Sophisticated Surveys has performed an initial analysis of these surveyrequirements to determine the cost of surveying different populations. The costs

per person surveyed are listed in the following table:

Sophisticated Surveys explores the forthcoming options cumulatively.

Region 18 to 25 26 to 40 41 to 50 51 and over

Silicon Valley $4.75 $6.50 $6.50 $5.00

Big cities $5.25 $5.75 $6.25 $6.25

Small towns $6.50 $7.50 $7.50 $7.25

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(a)Formulate a linear programming model to minimize costs while meeting all

survey constraints imposed by AmeriBank.

Ans. Let,

X1 is the no of people from Silicon Valley under age group 18-25



X4 is the no of people from Silicon Valley above age group 51

X5 is the no of people from big-cities under age group 18-25



X8 is the no of people from big-cities above age group 51

X9 is the no of people from small towns under age group 18-25



X12 is the no of people from small towns above age group 51

Min z=4.75 x1+ 6.50 x2+ 6.50 x3+5 x4+5.25 x5+5.75 x6+ 6.25 x7+ 6.25 x8+ 6.50

x9+ 7.50 x10+ 7.50 x11+ 7.25 x12

Constraints:

x1+ x2+ x3+ x4+ x5+ x6+ x7+ x8+ x9+ x10+ x11+ x12=2000 ……………………….……(1)

x1+ x2+ x3+ x4>=300………………………………………………………………………………..…. (2)

x5+ x6+ x7+ x8>=700 …………………………………………………………………………………. (3)

x9+ x10+ x11+ x12=>400……………………………………………………………………………... (4)

x1+x5+x9>=400 …………………………………………………………………………………….……. (5)

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x2+x6+x10>=5500……………………………………………………………………………………… . (6)

x3+x7+x11>=300……………………………………………………………………………………… ... (7)

x4+ x8+ x12>= 300……………………………………………………………………………….….…. (8)

x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12>=0………………………………….……..…..(9)

X1=600

X2=0

X3=0

X4=300X5=0

X6=550

X7=150

X8=0

X9=250

X10=0

X11=150

X12=0

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(b) If the profit margin for Sophisticated Surveys is 15 percent of cost, what bid

will they submit?

Ans. Given that the profit margin is 15%, Sophisticated Surveys will submit the

following bid:

= (2850+0+0+1500+0+3162.50+937.5+0+1625+0+1125+0)*1.15 $

= (11199.5)*1.15 $

=12879.4 $

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(c) After submitting its bid, Sophisticated Surveys is informed that it has the

lowest cost but that AmeriBank does not like the solution. Specifically, Rob feels

that the selected survey population is not representative enough of the banking

customer population. Rob wants at least 50 people of each age group surveyed in

each region. What is the new bid made by Sophisticated Surveys?

Ans. The additional constraints will look like:

X1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12 >50

The new bid will be:

= (237.50+325+975+250+262.5+625+3125+1950+4500+375+362.5)1.15

=14935.6 $

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(d) Rob feels that Sophisticated Surveys oversampled the 18- to 25-year-old

population and the Silicon Valley population. He imposes a new constraint that no

more than 600 individuals can be surveyed from the 18- to 25-year-old population

and no more than 650 individuals can be surveyed from the Silicon Valley

population. What is the new bid?

Ans. In addition to 1st 20 constraints of the 1st bid these two constraints are

added:

X1+x5+x9

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The new bid is= (11450)1.15

=1322.5 $

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(e) When Sophisticated Surveys calculated the cost of reaching and surveying

particular individuals, the company thought that reaching individuals in young

population would be easiest. In a recently completed survey, however,

Sophisticated Surveys learned that this assumption was wrong. The new costs for

surveying the 18- to 25-year-old population are listed below:

Region survey cost per

person

Silicon Valley $6.50

Big cities $6.75

Small towns $7.00

Given the new costs, what is the new bid?

Ans. The new costs are as follows:

x1=6.5$

x5=6.75 $

x9=7 $

As the constraints are changing we will see whether these changes in the current

objective coefficient will have an effect on the final output or not.

Is this current case we need to apply 100% Rule.

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From the above table we get the values of allowable increases of the decision

variables (for X1, X5, X9):

I1= (5.00-4.75) =0.25 & C1=6.50-4.75=1.75

I5= (5.25-5.25) =0 & C5=6.75-5.25=1.50

I9= (6.63-6.50) =0.13 & C9=7.00-6.50=0.50

Now,

R1=1.75/0.25=7.00 i.e. 700%

R5=1.50/0=

R9=0.50/0.13=3.8 i.e. 380%

∑rj= more than 1000%

So it’s far greater than 100%, the new z value will definitely.

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The new bid will be = (12012.5)*1.15

=13814.375 $

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(f) To ensure the desired sampling of individuals, Rob imposes even stricter

requirements. He fixes the exact percentage of people that should be surveyed

from each population. The requirements are listed below:

18 to 25 25%26 to 40 35%

41 to 50 20%

51 and over 20%

Silicon Valley 20%

Big cities 50%

Small towns 30%

By how much would these new requirements increase the cost of surveying for

Sophisticated Surveys? Given the 15 percent profit margin, what would

Sophisticated Surveys bid?

Ans. In the light of these stricter requirements imposed, there will be no change

in the objective function. Only a few constraints will be added. These have been

given below:

Min Z= 6.50 x1+ 6.50 x2+ 6.50 x3+5 x4+6.75 x5+5.75 x6+ 6.25 x7+ 6.25 x8+ 7.0 x9+

7.50 x10+ 7.50 x11+ 7.25 x12

But all the constrains can be rewritten as follows:

x1+ x2+ x3+ x4+ x5+ x6+ x7+ x8+ x9+ x10+ x11+ x12=2000……….……(1)

x1+x5+x9=500…………………………………………………………………………… .. (2)

x2+x6+x10=700………………………………………………………………………...… (3)

x3+x7+x11=400…………………………………………………………………………… (4)

x4+x8+x12=400……………………………………………………………………….… .. (5)

x1+ x2+ x3+ x4=400…………………………………………………………………..… (6)

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x5+ x6+ x7+ x8=1000…………………………………………………………………... (7)

x9+ x10+ x11+ x12=600………………………………………………………………… (8)

Total cost :( 0+0+0+2000+0+4025+1875+0+3500+0+750)1.15

= (12150)*1.15

=13972.5 $

lineal 4.2.pdf

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