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This is Production, costs and feasible profit.

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This walkthrough uses a generic synthetic narrator, not a
recording of Craig Wright.

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Pause whenever you need time to calculate.

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The original lesson, written walkthrough and exercises
accompany this video.

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Production transforms scarce resources.

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A workshop can produce more chairs yet earn less if additional
chairs sell cheaply or require costly

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overtime.

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It can also earn money while imposing a cost on people outside
the transaction.

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Keep three questions separate: what can be produced, what the
producer gains, and what happens to everyone

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affected.

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We begin with the technical relationship between inputs and
output, then add prices and opportunity costs.

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This sequence makes it easier to see which conclusions arise
from technology and which depend on markets,

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alternatives and values.

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A production function holds some things fixed.

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Imagine a workshop with one cutting machine and different
numbers of workers.

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Adding a worker can change how effectively the machine is used,
but adding a second machine is outside this

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particular short-run choice.

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A different business may adjust equipment much faster or
slower.

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The distinction is about available adjustment, not a fixed
calendar rule.

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The production relationship also assumes comparable worker
hours, skill and material quality.

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If those change across observations, a higher output cannot
automatically be attributed to worker numbers

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alone.

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Worked example: marginal product.

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Subtract each output from the next one.

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The first worker adds 12 minus zero.

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The second adds 28 minus 12, or 16.

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The third adds 39 minus 28, or 11.

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The fourth adds seven and the fifth adds four.

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Early specialisation can explain an initial rise in marginal
product; crowding around fixed equipment can

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explain a later decline.

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These are possible mechanisms, not facts established merely by
the table.

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Diminishing marginal product means smaller additions to output,
not necessarily falling total output or a

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judgement about any worker's individual worth.

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Average and marginal product differ.

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At two workers, output of 28 gives an average of fourteen.

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The third worker adds eleven units, below fourteen, so the new
average falls to thirteen.

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This is a general property of averages.

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A new observation below an existing average lowers that average
when weights are comparable.

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Average product and marginal product answer different
questions: output per worker across the whole team

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versus output added by a change in team size.

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Neither alone determines the profit-maximising workforce,
because we also need output prices, labour costs

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and any other costs caused by expansion.

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Classify costs along separate dimensions.

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Do not use fixed and sunk as synonyms.

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Suppose a workshop can cancel next month's room hire at no
charge.

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The hire is fixed over the month's feasible production range,
but avoiding it is relevant to whether the

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workshop opens.

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A non-refundable design payment made last year is sunk for
today's decision.

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A machine already owned may still have a resale or rental
alternative, creating an opportunity cost even if

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no new cash payment is needed.

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Classify costs for the specific decision and period rather than
attaching permanent labels without context.

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Cash surplus is not economic surplus.

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If an owner could earn money elsewhere during the same hours,
business receipts alone do not show whether

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operating improves their position.

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One method subtracts forgone alternative earnings from the
business cash surplus.

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Another adds remaining alternative earnings to business
receipts and compares that full allocation with

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working elsewhere throughout.

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Both should agree when they include the same costs and time.

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An accounting allocation may or may not reflect a relevant
sacrifice.

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Ask whether the decision changes cash spending, resource use or
the value of an available alternative.

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Worked example: contribution per unit.

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Begin with consistent time units.

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Divide twelve minutes by sixty to obtain 0.2 hours.

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Multiply by the available alternative hourly return of fifteen
pounds, giving a three-pound opportunity cost

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per unit.

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Subtract both the seven-pound cash cost and this time cost from
the selling price.

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Eight pounds remains to cover the costs that do not vary with
unit volume and then provide an economic

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surplus.

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This contribution assumes each extra sale leaves other sales
unchanged, uses the stated resources and fits

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within capacity.

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It is not yet the profit on an entire month.

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Worked example: build the monthly result.

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Check the result by two routes.

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The contribution route gives 30 times eight, or 240 pounds,
less fixed economic costs of 90 pounds plus four

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times 15 pounds, yielding 90 pounds.

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The cash route begins with 30 times 18 pounds revenue, or 540
pounds.

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Subtract 210 pounds variable cash costs and 90 pounds monthly
cash costs to get 240 pounds.

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Production takes thirty times 0.2 hours, or six hours, and
maintenance takes four more.

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Ten hours valued at 15 pounds cost 150 pounds in forgone
earnings.

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Subtracting that from cash surplus gives the same 90 pounds
economic result.

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Break-even depends on the decision.

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Write economic surplus as eight times quantity minus 150.

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Set it equal to zero, add 150 to both sides and divide by
eight.

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The result is 18.75, which is a planning boundary rather than a
possible whole-unit sale count.

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At eighteen units, contribution is 144 pounds and the business
is six pounds short.

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At nineteen, contribution is 152 pounds and the surplus is two
pounds.

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This threshold assumes unchanged prices, costs and product mix.

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If contribution were zero or negative, increasing volume alone
would not cover positive fixed costs within

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this linear model.

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Past expenditure does not force future production.

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A project can have been disappointing overall and still be
worth continuing from today, or have done well

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historically and now be worth stopping.

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The relevant question is what each available decision changes.

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Sunk-cost reasoning does not require forgetting the past: past
results can inform forecasts and reveal

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mistakes.

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It requires separating information from an unrecoverable
payment.

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Also check whether something described as sunk really is
unrecoverable.

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If the design could be licensed to someone else only when
unused by this business, that alternative would

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create a current opportunity cost.

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Capacity makes algebra conditional.

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Subtract fixed time before dividing by time per unit: twenty
minus four is sixteen, and sixteen divided by

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0.2 is eighty.

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At full capacity, an extra order cannot simply consume another
otherwise unused twelve minutes.

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It may displace an existing order, require overtime or require
someone else's help.

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Its opportunity cost must reflect that actual alternative.

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A constant-contribution formula is useful only while its
resource and pricing assumptions hold.

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Always check a proposed break-even or switching threshold
against capacity before presenting it as a

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feasible business plan.

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Worked example: choose a workforce.

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Multiply each output by twelve, then subtract one hundred
pounds per worker and the committed sixty pounds.

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For three workers, revenue is 39 times twelve, or 468 pounds;
costs are 300 pounds plus 60 pounds, leaving

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108 pounds.

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The fourth adds seven units worth 84 pounds but costs 100
pounds, reducing the result by 16 pounds.

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The fifth also reduces it.

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The first three additions increase the result, even though the
one-worker total remains negative after the

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committed cost.

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This example shows why marginal contributions and complete-plan
comparisons work together.

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The conclusion assumes all listed staffing options are
feasible.

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Profit guides choices under specific conditions.

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A business may discover a useful way to serve customers, or it
may benefit from restricted entry, misleading

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information or costs imposed on others.

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The same accounting label cannot distinguish those cases by
itself.

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A liberty-oriented approach values experimentation and
voluntary cooperation, while a careful analysis asks

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how rights, liability and competition shape the available
opportunities.

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Long-run entry can reduce some excess returns, but barriers,
innovation and uncertainty can sustain

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differences.

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Avoid turning a useful tendency into a promise that all markets
instantly reach identical returns or

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perfectly reward social value.

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Audit the production decision.

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A good business calculation should be reproducible by someone
who knows only the assumptions and arithmetic.

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Label pounds per unit, hours per month and total pounds
distinctly.

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Show intermediate values before rounding and explain whether an
average represents expected product mix or

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actual sales.

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Then test the assumptions most likely to reverse the choice,
such as demand, service time or the

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availability of alternative work.

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The numerical exercises check specified calculations.

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Their ungraded reflection fields ask you to identify what the
arithmetic leaves unresolved rather than

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pretending that an automatic marker can fully assess business
judgement.