ENGINEERING ECONOMY Chapter #2: Cost Concepts and Design Economics By: Eng. Ahmed Y Manama
Outline • Fixed, Variable, and Incremental Cost
• Recurring and Nonrecurring Costs
• Direct, Indirect and Overhead Costs • Cash Cost Versus Book Cost
• Sunk Cost and Opportunity Costs
Cost Estimating
Used to describe the process by which the
present and future cost consequences of engineering designs are forecast
Fixed, Variable, and Incremental Costs • Fixed costs: unaffected by changes in activity level over a feasible
range of operations for the capacity or capability available. • Typical fixed costs include: Insurance and taxes on facilities
General management and administrative salaries License fees Interest costs on borrowed capital.
• Fixed costs will be affected When: Large changes in usage of resources occur Plant expansion or shutdown is involved
Fixed, Variable, and Incremental Costs • Variable Costs: associated with an operation that vary in total
with the quantity of output or other measures of activity level. • Example of variable costs include : Costs of material and labor used in a product or service, because they
vary in total with the number of output units -- even though costs per unit remain the same.
Fixed, Variable, and Incremental Costs • Incremental Cost: additional cost that results from increasing
output of a system by one (or more) units. • Incremental cost is often associated with “go / no go” decisions
that involve a limited change in output or activity level. EXAMPLE: the incremental cost of driving an automobile might be $0.27 / mile. This cost depends on: 1.
mileage driven;
2.
mileage expected to drive;
3.
age of car;
RECURRING AND NONRECURRING COSTS • Recurring costs: repetitive and occur when a firm produces
similar goods and services on a continuing basis. • Variable costs are recurring because they repeat with each unit
of output. • A Fixed cost that is paid on a repeatable basis is also a recurring
cost: Office space rental
RECURRING AND NONRECURRING COSTS • Nonrecurring costs: not repetitive, even though the total
expenditure may be cumulative over a relatively short period of time; • Typically involve developing or establishing a capability or
capacity to operate; • Examples are purchase cost for real estate upon which a plant
will be built, and the construction costs of the plant itself;
Direct, Indirect and Overhead Costs • Direct Costs can be reasonably measured and allocated to a
specific output or work activity labor and material directly allocated with a product, service or
construction activity;
• Indirect Costs are difficult to allocate to a specific output or
activity costs of common tools, general supplies, and equipment maintenance ;
• Overhead consists of plant operating costs that are not direct
labor or material costs indirect costs, overhead and burden are the same;
Cash Cost Versus Book Cost • Cash cost is a cost that involves payment in cash and results in
cash flow; • Book cost or noncash cost is a payment that does not involve cash transaction book costs represent the recovery of past expenditures over a fixed
period of time;
• Depreciation is the most common example of book cost; depreciation is what is charged for the use of assets, such as plant and equipment; depreciation is not a cash flow;
Sunk Cost and Opportunity Cost • Sunk Cost is one that has occurred in the past and has no
relevance to estimates of future costs and revenues related to an alternative course of action; • Opportunity Cost is the cost of the best rejected ( i.e., foregone
) opportunity and is hidden or implied;
Example A municipal solid-waste site for a city must be located at Site A or Site B. After sorting, some of the solid refuse will be transported to an electric power plant where it will be used as fuel. Data for the hauling of refuse from each site to the power plant are shown in Table P2-4.
If the power plant will pay $8.00 per cubic yard of sorted solid waste delivered to the plant, where should the solid-waste site be located? Use the city’s viewpoint and assume that 200,000 cubic yards of refuse will be hauled to the plant for one year only. One site must be selected. Solution
Consumer and Producer Goods and Services • Consumer goods and services are those products or services
that are directly used by people to satisfy their wants. Food, clothing, homes, cars , television sets, haircuts, opera, and medical services are examples • Producer goods and services are used to produce consumer
goods and services or other producer goods. Machine tools,
factory buildings, buses, and farm machinery are examples.
Utility And Demand • Utility is a measure of the value which consumers of a product
or service place on that product or service; • Demand is a reflection of this measure of value, and is represented by price per quantity of output
• The demand for a product or service
is directly related to its price according to P = a‐bD where p is price, D is demand, and a and b are constants that depend on the particular product or service. • a=Y‐axis (quantity) intercept, (price at 0 amount demanded) • b = slope of the demand function
Total Revenue Function • Total revenue is the product of the selling price per unit, p, and
the number of units sold, D.
Total Revenue Function as a Function of Demand • The demand, D, that will produce maximum total revenue
can be obtained by solving
Cost, Volume, and Breakeven Point Relationships • At any demand D, total cost is
• For the linear relationship assumed here,
where
𝐶𝑣 is the variable cost per unit.
The optimal demand at which maximum profit will occur by taking the first derivative of the last Equation with respect to D and setting it equal to zero:
Example P 2-12. A company produces circuit boards used to update outdated computer equipment. The fixed cost is $42,000 per month, and the variable cost is $53 per circuit board. The selling price per unit is p = $150−0.02 D. Maximum output of the plant is 4,000 units per month. a. Determine optimum demand for this product. b. What is the maximum profit per month? c. At what volumes does breakeven occur? d. What is the company’s range of profitable demand?
Home Work Assignments HW𝟐 1, 3 , 9 ,13 ,14 ,15 ,17 , 19 Deadline 2/11/2014
