# 7.3 The structure of costs in the long run  (Page 3/26)

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[link] illustrates the idea of economies of scale, showing the average cost of producing an alarm clock falling as the quantity of output rises. For a small-sized factory like S, with an output level of 1,000, the average cost of production is $12 per alarm clock. For a medium-sized factory like M, with an output level of 2,000, the average cost of production falls to$8 per alarm clock. For a large factory like L, with an output of 5,000, the average cost of production declines still further to \$4 per alarm clock.

The average cost curve in [link] may appear similar to the average cost curves presented earlier in this chapter, although it is downward-sloping rather than U-shaped. But there is one major difference. The economies of scale curve is a long-run average cost curve, because it allows all factors of production to change. The short-run average cost curves presented earlier in this chapter assumed the existence of fixed costs, and only variable costs were allowed to change.

One prominent example of economies of scale occurs in the chemical industry. Chemical plants have a lot of pipes. The cost of the materials for producing a pipe is related to the circumference of the pipe and its length. However, the volume of chemicals that can flow through a pipe is determined by the cross-section area of the pipe. The calculations in [link] show that a pipe which uses twice as much material to make (as shown by the circumference of the pipe doubling) can actually carry four times the volume of chemicals because the cross-section area of the pipe rises by a factor of four (as shown in the Area column).

Comparing pipes: economies of scale in the chemical industry
Circumference ( $2\pi r$ ) Area ( $\pi {r}^{2}$ )
4-inch pipe 12.5 inches 12.5 square inches
8-inch pipe 25.1 inches 50.2 square inches
16-inch pipe 50.2 inches 201.1 square inches

A doubling of the cost of producing the pipe allows the chemical firm to process four times as much material. This pattern is a major reason for economies of scale in chemical production, which uses a large quantity of pipes. Of course, economies of scale in a chemical plant are more complex than this simple calculation suggests. But the chemical engineers who design these plants have long used what they call the “six-tenths rule,” a rule of thumb which holds that increasing the quantity produced in a chemical plant by a certain percentage will increase total cost by only six-tenths as much.

## Shapes of long-run average cost curves

While in the short run firms are limited to operating on a single average cost curve (corresponding to the level of fixed costs they have chosen), in the long run when all costs are variable, they can choose to operate on any average cost curve. Thus, the long-run average cost (LRAC) curve    is actually based on a group of short-run average cost (SRAC) curves , each of which represents one specific level of fixed costs. More precisely, the long-run average cost curve will be the least expensive average cost curve for any level of output. [link] shows how the long-run average cost curve is built from a group of short-run average cost curves. Five short-run-average cost curves appear on the diagram. Each SRAC curve represents a different level of fixed costs. For example, you can imagine SRAC 1 as a small factory, SRAC 2 as a medium factory, SRAC 3 as a large factory, and SRAC 4 and SRAC 5 as very large and ultra-large. Although this diagram shows only five SRAC curves, presumably there are an infinite number of other SRAC curves between the ones that are shown. This family of short-run average cost curves can be thought of as representing different choices for a firm that is planning its level of investment in fixed cost physical capital—knowing that different choices about capital investment in the present will cause it to end up with different short-run average cost curves in the future.

what is elastic
how is equilibrium defined in financial market?
what is the definition of money
infinity
Money is define as anything that is generally acceptable as a means of exchange nd settlement of dept
Simeon
how do choices end up determining what, how and for whom goods and services are produced
there are 10 000 seats available for the Wimbledon tennis Championships. the price per ticket is fixed by the organisers. the supply of seats is thus: A. completely elastic B. completely inelastic C. elastic D. unitary elastic E. elastic which option is the answer?
the trade between two or more countries outside the territory of own country
Mukeem
Ivan
Antony
how do monopolistic firm make profit in the short run and long run
oligopolistic competition is known to have a kinked demand curve .why there is such a tease my in oligopolistic form only
Ediga
please can anyone help me in econs
Oppong
Manuel in which context
Daizy
Oppong
what is demand ?
The amount of some goods or services consumers need to purchase
The amount of goods or services that consumers are willing and can afford to purchase.
Ivan
it is goods and services consumers are willing and able to buy at given price over a given period of time
Rebecca
as quantity of good and service that a consumer is willing and able to purchase at a given price and at the particular market price.
MOHAMMED
The amount of goods and services consumers are able and willing to buy and pay for at a given price and at given point in time.
Solomon
refers to the quantity of goods and services that customers are willing and able to purchase at various prices over a period of time
Ryt
what are subsidies
how do trade unions deal with subsidies
Yaya
bro can you explain decision making
WhatsApp
Decision making is a process to use your limited resources for best productive purpose.
Dipam
explain why an increase in national income may not always lead to improvement in economic wellbeing of all the citizens?
Mendo
How many types of labour do we have pls
ROA
two
nabil
skilled and unskilled labour
nabil
Thanks 🙏
ROA
what are the factors that affects efficiency of labour ?
nabil
What are tools of economics analysis
Adu Tumwah,,, The tools of economics analysis are; Charts, graphs, equations, table, arithemetic mean, etc.
Dennis
Subsidies are payments made by the government to the producers of goods and services
Daizy
what is the marginal revenue if p=10-2q
what's the difference between demand goods and supply gooda
why is 2% the optimal inflation rate in many countries
Spiff
why is 2% the optimal inflation rate in many countries
Spiff
what's inflation
a general rise in the prices of services and goods in a particular country
Spiff
why is 2% the optimal inflation rate in many countries?
amina
resulting in a fall in the value of money,,
Spiff
for example
Spiff
Inflation is the continuous rise of price of goods and services in a nation
Oluchi
persistent increase in the general price level
Anyere
what will the effective demand if inflation is constant and real wage is less then money wage ?
to start
Dennis
to start with your question i think we have to break it down into key words, and they effective demand ,inflation and real wages ... Ok when we say demand is effective we mean the demand is backed up by capital .. it is backed up by the ability to pay for the good/commodity demanded for
Dennis
in other hand inflation is the persistent rise of goods and services in and particular country's economy
Dennis
so what is real wages it means the amount paid to labour for a particular work done
Dennis
money wage is the money/capital paid to a worker
Dennis
Dennis
What is monopoly
I believe that a market is monopolistic if there is no competition. in other words, a given company is the only one offering the product/service.
amina
am a fan of monopoly
Okeke
it is correct
Spiff
and in other word,,, is a thing that belongs to one person or group that another people will not able to share
Spiff
a single seller and large number of consumer
Vipul
A monopoly is a firm that is the sole producer of a good or service for which there are no close substitutes. It exist because of barriers to entry. The barriers can be legal or natural.
Dennis
Ok
Oluchi
give tree difference between economic good and free good
economic goods produced by man efforts and free goods are free by nature
Kobwa
What are tools of economics analysis
economics provides tools to know our better desire and how to get maximum utility and right way right time decission power.
Inno
economic good are related to income to fullfill satisfaction and free goods are natural resourses like sunshine rain air water from earth e.t.c
Inno
graphs,pie chart,histograms,tables,curves,etc.
nabil
why do government sometimes impose indirect taxes rather than direct taxes.
nabil
just five points with no explanations
nabil
what is want
anything just come from your heart
domingo
no matter how much you give
domingo
is what you desire to have
Tsai
their the human desire it's need(s).
Gideon
YES
Erik
like medicine food etc
domingo