Notes on Engineering Economics Unit I

UNIT‐1
Introduction to Engineering Economics and Ma
nagerial Economics (5 Hrs.)

UNIT‐1: INTRODUCTION TO ENGINEERING EC
ONOMICS AND MANAGERIAL ECONOMICS (5
HRS.)
• Concept of Efficiency
• Theory of Demand, Elasticity of Demand,
• Supply and Law of Supply
• Indifference Curves, Budget Line, Welfare Anal
ysis
• Scope of Managerial Economics
• Techniques and Applications of Managerial Econo
mics.
9/9/2016Deepak Srivastava
2

WHAT IS EFFICIENCY?
•Efficiency is a level of
performance that describes a
process that uses the lowest
amount of inputs to create
the greatest amount of inputs.
3

EFFICIENCY
• In popular discussion, business decision
making, and government policies, three
different types of efficiency concepts are
encountered. These are engineering,
technical, and economic efficiency. Each is a
valid concept, and each conveys useful
information.
4

ENGINEERING EFFICIENCY
• Engineering efficiency refers to the physical amount
of some single key input that is used in
production. It is measured by the ratio of that input
to output.
• For example:
• The engineering efficiency of an engine refers to the
ratio of the amount of energy in the fuel burned
by the engine to the amount of usable energy
produced by the engine.
5

ENGINEERING EFFICIENCY
• Saying that a steam engine is 40 percent efficient
means that 40 percent of the energy in the fuel that
is burned in the boiler is converted into work that is
done by the engine, while the other 60 percent is
lost.
• Note that engineering efficiency is expressed in
terms of the use of a single input and does not
involve financial considerations—it is purely about
physical relationships.
6

TECHNICAL EFFICIENCY
•Technical efficiency is related to the
physical amount of all factors used in the
process of producing some product.
• A particular method of producing a given level
of output is technically efficient if there
are no other ways of producing the output
that use less of at least one input while not
using more of any others.
7

EXAMPLE…
• For example, consider a firm that is currently
using 100 units of labour and 50 units of
capital to produce a certain level of output.
If the firm could maintain its current output
level by using only 90 units of labour without
using more capital, then it is being technically
inefficient in its current methods because it is
“wasting” 10 units of labour.
8

ECONOMIC EFFICIENCY
•Economic efficiency is related to the
value (rather than the physical amounts) of
all inputs used in producing a given output.
• The production of a given output is
economically efficient if there are no
other ways of producing the output that
use a smaller total value of inputs.
9

EXAMPLE…
• For example, a firm may have several alternative
production methods that it could use. One may
require a lot of labour but only a little capital
whereas another requires a lot of capital and only a
little labour. A third production method may require
a lot of land but relatively little of both labour and
capital. In order to maximize its profits, the
firm should choose the production method that
costs the least.
10

THEORY OF DEMAND…
• Theory of Demand
• What is demand ?
• “Demand for anything means the quantity of that commodity, which
is desired to be bought, at a given price, per unit of time.”
• It is interpreted as your want backed up by your purchasing power.
11
Demand for a
commodity
implies:
Desire to acquire
it,
Willingness to
pay for it, and
Ability to pay for
it.

TYPES OF DEMAND.
Direct and derived demand
Recurring and replacement demand
Complementary and competing demand
Demand for capital goods and consumer goods
Demand for perishable goods and durable goods
Individual and market demand
12

DETERMINANTS OF DEMAND
• The demand for a commodity arises from the
consumer’s willingness and ability to purchase the
commodity. The demand theory says that the quantity
demanded of a commodity is a function of or depends
on not only the price of a commodity, but also on
income of the person, price of related goods – both
substitutes and complements – tastes of consumer,
price expectation and all other factors. Demand
function is a comprehensive formulation which
specifies the factors that influence the demand for the
product.
13

DETERMINANTS OF DEMAND
Dx = Demand for item x
Px = Price of item x
Py = Price of substitutes
Pz = Price of complements
B = Income of consumer
E = Price expectation of the user
A = Advertisement Expenditure
T = Taste or preference of user Notes
U = All other factors
14

THE DEMAND FUNCTION
Dx = f(Px, Py, Pz, B, A, E, T, U)
15

THE RELATIONSHIP…
16

DEMAND SCHEDULE AND DEMAND
CURVE
• A demand curve considers only the price-demand
relation, other factors remaining the same. The
inverse relationship between the price and the
quantity demanded for the commodity per time
period is the demand schedule for the commodity
and the plot of the data (with price on the vertical
axis and quantity on the horizontal axis) gives the
demand curve of the individual.
17

0
0.5
1
1.5
2
2.5
Demand for
X
PriceofX
Demand Curve
19

2.3 ELASTICITY OF DEMAND
• 2.3 Elasticity of Demand and its measurement.
• Price Elasticity.
• Income Elasticity.
• Cross Elasticity and
• Advertising Elasticity.
20

ELASTICITY OF DEMAND
•Introduction Elasticity is the measure of responsiveness.
It is the ratio of the percent change in one variable to the percent
change in another variable.
The key thing to understand is that we use elasticity when we want
to see how one thing changes when we change something else.
How does demand for a good change when we change its price?
How does the demand for a good change when the price of a
substitute good changes?
21

CONCEPT OF ELASTICITY
•The law of demand tells us that
consumers will respond to a price
decline by buying more of a product. It
does not, however, tell us anything
about the degree of responsiveness of
consumers to a price change. The
contribution of the concept of elasticity
lies in the fact that it not only tells us
that consumer's demand responds to
price changes but also the degree of
responsiveness of consumers to a price
change. The figure shows two demand
curves. Let Da be the demand for
cheese in Switzerland and Db be the
demand for cheese in England.
22

CLASSIFICATION OF DEMAND CURVES
ACCORDING TO THEIR ELASTICITIES
•Depending on how the total revenue changes, when price
changes we can classify all demand curves in the following five
categories:
1. Perfectly inelastic demand curve
2. Inelastic demand curve
3. Unitary elastic demand curve
4. Elastic demand curve
5. Perfectly elastic demand curve 9/9/2016Deepak Srivastava
23

Perfectly Inelastic Demand : These are certain goods like salt, match box
etc. whose demand neither increase nor decrease with a change in price.
A perfectly inelastic demand curve is a vertical straight line parallel to Y –axis which shows
that whatever may be the change in price the demand will remain constant at OQ.
24

Perfectly Elastic Demand : That is [ed = ∞]. When the quantity demanded of a commodity changes
infinitely due to a slight or no decrease in price, such goods are said to have perfectly elastic demand.
A perfectly Elastic Demand Curve is a straight line parallel to X –axis.
25

Relatively Inelastic Demand (ed < 1)
In this type of goods and services the proportionate change in quantity demand is less than the change in
price. These are mostly essential goods of daily use like rice, wheat etc.
In the diagram change in quantity QQ1 is less than proportionate to the change in price
PP1.
26

Relatively Elastic Demand : In such type of goods the percentage change in quantity demanded
of a commodity is more than proportionate to the percentage change in price, eg. luxury car.
In the diagram we see that change in quantity demanded QQ1 is more than proportionate
to the change in price PP1.
27

Unit Elastic Demand (ed = 1)
Here the rate of change in demand is exactly equal to the rate of change in price. Therefore the products or
service with unit elasticity are neither elastic nor inelastic.
A Unit elastic Demand curve is a rectangular - hyperbola as shown above
28

NUMERICAL MEASUREMENT OF ELASTICITY
• What does it mean when we say that the elasticity of demand is
0.5? 0.4? 2.3? To answer this question we have to examine the
following definition for elasticity coefficient, Ed.
29

SUPPLY AND LAW OF SUPPLY
• Supply
• Supply is the specific quantity of output that the producers are willing
and able to make available to consumers at a particular price over a
given period of time. In one sense, supply is the mirror image of
demand. Individuals’ supply of the factors of production or inputs to
market mirrors other individuals’ demand for these factors. For
example, if we want to rest instead of weeding the garden, we hire
someone: we demand labour. For a large number of goods, however,
the supply process is more complicated than demand.
• The supply of produced goods (tangibles) is usually indirect and the
supply of non-produced goods (intangibles) is more direct. Individuals
supply their labour in the form of services directly to the goods
market. For example, an independent contractor may repair a
washing machine. The contractor supplies his labour directly.
31

LAW OF SUPPLY
• According to the Law of Supply, other things remaining constant,
higher the price of a commodity, higher will be the quantity
supplied and vice versa. There is a positive relationship between
supply and price of a commodity.
32

MARKET EQUILIBRIUM
PRICE IS DETERMINED BY THE TWO FORCES OF DEMAND AND SUPPLY, IN A
FREE MARKET. A POINT OF BALANCE, WHERE DEMAND EQUALS SUPPLY IS
KNOWN AS MARKET EQUILIBRIUM.
33

INDIFFERENCE CURVES
• An indifference curve may be defined as the locus of points.
Each point represents a different combination of two
substitute goods, which yields the same utility or level of
satisfaction to the consumer. Therefore, he/she is indifferent
between any two combinations of goods when it comes to
making a choice between them. Such a situation arises
because he/she consumes a large number of goods and
services and often finds that one commodity can be
substituted for another. This gives him/her an opportunity to
substitute one commodity for another, if need arises and to
make various combinations of two substitutable goods which
give him/her the same level of satisfaction. If a consumer
faced with such combinations, he/she would be indifferent
between the combinations. 9/9/2016Deepak Srivastava
34

FIGURE BELOW SHOWS THE INDIFFERENCE CURVE DRAWN ON THE BASIS OF
THE FIGURE GIVE IN TABLE. IT DEPICTS, IN GENERAL, ALL COMBINATIONS OF
TWO GOODS WHICH YIELD THE SAME LEVEL OF SATISFACTION TO THE
CONSUMER. THE CONSUMER IS INDIFFERENT ABOUT ANY TWO POINTS
LYING ON THIS CURVE.
36

ASSUMPTIONS
• The following assumptions about the consumer psychology are
implicit in indifference curve analysis:
• Transitivity: If a consumer is indifferent to two combinations of two
goods, then he is unaware of the third combination also.
• Diminishing marginal rate of substitution: The rarer the availability
of a good, the greater is its substitution value. For example, water
has a high substitution value as it is a scarce resource.
• Rationality: The consumer aims to maximise his total satisfaction
and has got complete market information.
• Ordinal utility: Utility in this approach is not measurable. A
consumer can only specify his preference for a particular
combination of two goods, he cannot specify how much.
37

PROPERTIES OF INDIFFERENCE CURVE
• Indifference curves have the four basic characteristics:
• 1. Indifference curves have a negative slope
• 2. Indifference curves are convex to the origin
• 3. Indifference curves do not intersect nor are they tangent to one
another
• 4. Upper indifference curves indicate a higher level of satisfaction.
• These characteristics or properties of indifference curves, in fact,
reveal the consumer’s behaviour, his choices and preferences. They
are, therefore, very important in the modern theory of consumer
behaviour. Now, we will observe their implications.
38

BUDGET LINE
• THE BUDGET CONSTRAINT Having described preferences,
next we determine the consumer’s alternatives. The amount
of goods he can purchase depends on his available income
and the goods’ prices. Suppose the consumer sets aside Rs.
200 each week to spend on the two goods. The price of good
X is Rs. 40 per unit, and the price of Y is Rs. 20 per unit. Then
he is able to buy any quantities of the goods (call these
quantities X and Y) as long as he does not exceed his income.
If he spends the entire Rs. 200, his purchases must satisfy:
39
40X + 20Y = 200

CONSUMER EQUILIBRIUM
• If we superimpose the indifference map and
budget line as in Figure shown above, we find
that a consumer has to decide to purchase a
particular combination (C) as it falls on his
budget line, though a different combination
(D) would be more desirable as it will give a
higher level of satisfaction. At his point of
equilibrium C, the price line is touching the
indifference line tangentially meaning that the
slopes are equal. The slope of indifference
curve indicates the marginal rate of
substitution between X and Y, and the slope of
budget line indicates the ratio of price of X to
that of Y. Thus the principle of consumer's
equilibrium works out; the marginal rate of
substitution between X and Y must be
proportional to the ratio of price of X to that
of Y.
41

SCOPE OF MANAGERIAL
ECONOMICS
• Study of managerial economics essentially involves the
analysis of certain major subjects like:
• Demand analysis and methods of forecasting
• Cost analysis
• Pricing theory and policies
• Profit analysis with special reference to break-even point
• Capital budgeting for investment decisions
• The business firm and objectives
• Competition.
51

SCOPE OF MANAGERIAL ECONOMICS
There are four groups of problem in
both decision making and forward
planning.
Resource
allocation
Inventory
and
queuing
problem
Pricing
problems
Investment
problems
52

SCOPE OF MANAGERIAL
ECONOMICS
• A firm applies principles of economics to answer these
questions. The first question relates to what goods and services
should be produced and in what quantities. Demand theory
guides the manager in the selection of goods and services for
production. It analyses consumer behavior with regard to:
• Type of goods and services they are likely to purchase in the
current period and in the future, Goods and services which
they may stop consuming,
• Factors influencing the consumption of a particular good or
service, and
• The effect of a change in these factors on the demand of
that particular good or service.
53

SCOPE OF ECONOMICS
• Microeconomics
• Macroeconomics
• International economics
• Public finance
• Development economics
• Health economics
• Environmental economics
• Urban and rural economics
54

MICRO & MACROECONOMICS
• Subject- matter of economics can be sub- divided in to
Microeconomics and Macroeconomics.
• These terms were first coined and used by Ragnar Frisch.
• Acc. To K E Boulding:
• “Microeconomics is the study of particular firms, particular
households, individual prices, wages, incomes, individual industries,
particular commodities.”
• “Macroeconomics deals not with individual quantities as such but
with aggregates of these quantities, not with individual incomes but
with national income; not with individual prices but with general price
level; not with individual output but with national output.”
55

MANAGERIAL ECONOMICS AND ITS
RELEVANCE IN BUSINESS DECISIONS.
• To quote Mansfield, "Managerial Economics is concerned with the
application of economic concepts and economic analysis to the problems
of formulating rational managerial decisions."
• According to McNair and Meriam, "Managerial economics is the use of
economic modes of thought to analyse business situations."
• "Managerial Economics is concerned with the application of economic
principles and methodologies to the decision making process within the
firm or organisation under the conditions of uncertainty," says Prof. Evan J
Douglas.
• Spencer and Siegelman define it as "The integration of economic theory
with business practice for the purpose of facilitating decision making and
forward planning by management."
• According to Hailstones and Rothwel, "Managerial economics is the
application of economic theory and analysis to practice of business firms
and other institutions."
57

MANAGERIAL ECONOMICS
•Coordination
•An activity or an ongoing
process
•A purposive process
•An art of getting things
done by other people.
Management
•Human wants are virtually
unlimited and insatiable,
and
•Economic resources to
satisfy these human
demands are limited.
Economics •Thus managerial
economics is the study of
allocation of resources
available to a firm or a unit
of management among
the activities of that unit.
Managerial
Economics
58

RELATIONSHIP OF MANAGERIAL
ECONOMICS WITH DECISION SCIENCES
• Economics is linked with various other fields of study
like:
• Operation Research
• Theory of Decision Making
• Statistics
• Management Theory and Accounting
• Satisficing instead of maximizing
• Managerial Accounting
Economics and other Disciplines
59

Notes on Engineering Economics Unit I

Business decision making is essentially a
process of selecting the best out of
alternative opportunities open to the
firm.
The steps in next slides put managers’
analytical ability to test and determine
the appropriateness and validity of
decisions in the modern business world.

1. Establish objectives
2. Specify the decision problem
3. Identify the alternatives
4. Evaluate alternatives
5. Select the best alternatives
6. Implement the decision
7. Monitor the performance

Modern business conditions are changing
so fast and becoming so competitive and
complex that personal business sense,
intuition and experience alone are not
sufficient to make appropriate business
decisions. It is in this area of decision
making that economic theories and tools
of economic analysis contribute a great
deal.

Economic theory offers a variety of
concepts and analytical tools which
can be of considerable assistance to
the managers in his decision making
practice. These tools are helpful for
managers in solving their business
related problems. These tools are
taken as guide in making decision.

• Opportunity cost
• Incremental principle
• Principle of the time perspective
• Discounting principle
• Equi-marginal principle

OPPORTUNITY COST
• An opportunity cost refers to a benefit that a
person could have received, but gave up, to
take another course of action. Stated
differently, an opportunity cost represents an
alternative given up when a decision is made.
This cost is therefore most relevant for two
mutually exclusive events, whereby choosing
one event, a person cannot choose the other.
67

INCREMENTAL PRINCIPLE
• The incremental concept is probably the most important concept in
economics and is certainly the most frequently used in Managerial
Economics. Incremental concept is closely related to the marginal cost and
marginal revenues of economic theory.
• The two major concepts in this analysis are incremental cost and
incremental revenue. Incremental cost denotes change in total cost,
whereas incremental revenue means change in total revenue resulting
from a decision of the firm.
• The incremental principle may be stated as follows:
• A decision is clearly a profitable one if
• It increases revenue more than costs.
• It decreases some cost to a greater extent than it increases others.
• It increases some revenues more than it decreases others.
• It reduces costs more than revenues
68

PRINCIPLE OF THE TIME
PERSPECTIVE
• “a decision by the firm should take into account of both short-run
and long-run effects on revenues and cost & maintain the right
balance between the long run and short run.
• Short-run refers to a time period in which some factors are fixed
while others are variable. The production can be increased by
increasing the quantity of variable factors. While long-run is a time
period in which all factors of production can become variable.
• Entry and exit of seller firms can take place easily. From consumers
point of view, short-run refers to a period in which they respond to
the changes in price, given the taste and preferences of the
consumers, while long-run is a time period in which the consumers
have enough time to respond to price changes by varying their
tastes and preferences.
69

DISCOUNTING PRINCIPLE
• This concept is an extension of the concept of time perspective.
Since future is unknown and incalculable, there is lot of risk and
uncertainty in future. Everyone knows that a rupee today is worth
more than a rupee will be two years from now. This appears similar
to the saying that “a bird in hand is more worth than two in the
bush.” This judgment is made not on account of the uncertainty
surrounding the future or the risk of inflation.
• It is simply that in the intervening period a sum of money can earn
a return which is ruled out if the same sum is available only at the
end of the period. In technical parlance, it is said that the present
value of one rupee available at the end of two years is the present
value of one rupee available today. The mathematical technique for
adjusting for the time value of money and computing present value
is called ‘discounting’.
70

EQUI-MARGINAL PRINCIPLE
• An optimum allocation cannot be achieved if the value of the marginal
product is greater in one activity than in another. It would be, therefore,
profitable to shift labour from low marginal value activity to high marginal
value activity, thus increasing the total value of all products taken together.
• If, for example, the value of the marginal product of labour in activity A is Rs.
50 while that in activity В is Rs. 70 then it is possible and profitable to shift
labour from activity A to activity B. The optimum is reached when the values
of the marginal product is equal to all activities. This can be expressed
symbolically as follows:
• VMPLA = VMPLB = VMPLC = VMPLD = VMPLE
• Where VMP = Value of Marginal Product.
• L = Labour
• ABCDE = Activities i.e., the value of the marginal product of labour employed
in A is equal to the value of the marginal product of the labour employed in В
and so on. The equimarginal principle is an extremely practical notion.
71

Notes on Engineering Economics Unit I

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