ACCA Paper F2 – Management accounting
Course slides
Syllabus A
The nature and purpose of cost and management accounting
B
Cost classification, behaviour and purpose
C
Business mathematics and computer
D
spreadsheets Cost accounting techniques
E
Budgeting and standard costing
F
Short-term decision-making techniques
Slide 6
Format of the Exam
Format of the Exam 1 mark question
Marks
10 questions
10
Paper based exam: All multiple choice with a choice of 2 or 3 answers. Predominantly „wordy‟ questions.
2 mark questions
Total Slide 7
40 questions
80
Paper based exam: All multiple choice with a choice of 4 answers including words and calculations. 90
The BPP Learning Media classroom slides What do these slides cover? – A selection of key areas of the syllabus
Using the slides – Use the slides as a point of reference – Add detail by talking around the slides (eg using material from the corresponding Study Text chapter) – Consider adding slides yourself to suit your course – Recommend students attempt appropriate questions from the Practice & Revision Kit
Slide 8
Chapter 1
Study Text Chapter 1
Information for management
Purpose
• Assist management in running their business to achieve an overall objective • What is the overall objective of a business?
Slide 10
Data and information
• Data is the RAW MATERIAL
• Information is the PROCESSED DATA
Slide 11
Planning, control and decision making • Planning – Long term strategies – Short term targets • Control – Performance of the organisation – Review corporate plan • Decision making – autonomy of managers
Slide 12
Key roles of a management accountant • Costing • How to put a cost on our products and services
• Decision-making • What to produce/how should we finance it etc • Assessment of business requirements/budgeting • Planning
• Control • Assessing inefficiencies
• Performance Evaluation • Comparison to targets
Slide 13
Chapter 2
Study Text Chapter 2
Cost classification
Introduction • Arrange costs into logical groups – By function e.g. production, admin, finance – By nature e.g. labour, materials, stationery
• Grouping by function: Pool of costs
Production costs
Slide 15
Non production costs
Introduction • Grouping by nature: Pool of costs
materials
Slide 16
Labour
Expenses
Cost classification £ Productioncosts
Non-production costs TOTAL COST/EXPENSES
Slide 17
X
X X
Direct Prod‟n cost Indirect Prod‟n cost
Admin costs Selling & Distribution
Cost classification Direct Production costs Directmaterials Direct labour Directexpenses Indirect Production costs Indirectmaterials Indirectlabour Indirectexpenses TotalProductioncosts Non-production costs Administrationcosts Selling and distribution costs TOTACLOSTS Slide 18
X X X X X X X X X X
A typical cost card for a cost unit Direct Production costs Direct materials (5kg @ $3/kg) Direct labour (3hrs @ $6/hr) PRIME COST Indirect Production costs Variableoverheads Fixedoverheads FULLPRODUCTCOST
Slide 19
15.00 18.00 33.00 2.00 3.00 38.00
Terminology • Cost object • Cost unit • Divisional structures – Cost centre – Profit centre – Revenue centre – Investment centre
Slide 20
Chapter 3
Study Text Chapter 3
Cost behaviour
Accountant‟s Linear Assumption •Accountant‟s version •Economist‟s version
Y = a + bX
Total cost ($) Variable cost (VC)
Fixed cost (FC) output
Total cost = Fixed cost + (VC/unit x Output) Slide 22
„Hi-Low‟ Method Four step approach 1. Find the highest and the lowest output and the total costs at these levels of output. 2. Find the difference in output units and total cost. 3. Calculate the variable cost per unit (VC/unit). 4. Calculate the fixed cost by substitution.
Slide 23
Chapter 4
Study Text Chapter 4
Correlation and regression; expected values
Costs vs output - scattergraph
$
y = a + bx
(y) dependent variable
(x)
output independent variable
Slide 25
Linear regression • Finds the mathematical line of best fit y = a + bx b= n xy- x y 2
2
n x - ( x) a=
y-b x n
Slide 26
n
Correlation coefficient r=
n xy- x y ([n (x2)- ( x) 2][n (y2)-(
y) 2])
-1 < r < +1
Slide 27
r = +1
- perfect positive correlation
r = -1
- perfect negative correlation
r=0
- no correlation
Coefficient of determination The amount of variation in y which appears to be explained by variation in x Does NOT prove “cause and effect” Coefficient of determination = r2
Slide 28
Expected Values • Long term weighted average of possible outcomes: • Expected Value (EV) = np – If +ve EV = accept – If -ve EV = reject
Slide 29
Chapter 5
Study Text Chapter 5
Spreadsheets
Definition
• Electronic piece of paper • Divided into rows and columns • Data is input into „cells‟ i.e. A5, D8 • Data can either be numbers, text or symbols • Output is derived by applying a formula to data cells e.g. addition A5 + D8 Slide 31
Uses of spreadsheets • Preparation of management accounts • Cash flow analysis, budgeting and forecasting • Account reconciliation • Revenue and cost analysis • Comparisons and variance analysis • Sorting and categorisation of data Slide 32
Formulae with conditions • We can build a range of options into our data • = IF (logical_test, value_if_true, value_if_false) Example • = IF (A5>500,”Hurray!”,”More Sales Please!”)
Slide 33
Presentation of spreadsheets • Split into sections; Inputs, Calculations and Results • Use titles and column and row headings data source and purpose of • State spreadsheet
• Apply consistent format i.e. 2 decimal places • Use colours, borders and shadings to highlight and differentiate Slide 34
Chapter 6
Study Text Chapter 6
Material costs
Order, receipt and issue of raw materials Purchase requisition
Purchase order
Goods received note
Slide 36
Accounting for materials Materials inventory account (1) Material purchased X
__ X
Slide 37
(2) Issues to production X
c/d closing inventory balance
X
__ X
Monitoring inventory levels • To maintain accurate records of inventory • Visual methods of inventory control • Theoretical methods of inventory control – Re-order level – Minimum level – Maximum level
Slide 38
Learn for the exam
Costs associated with stock
Purchase costs
PxD
+ Order costs
C x D/Q
+ Holding costs
H x Q/2
= TOTAL COSTS Slide 39
WANT TO MINIMISE THESE
Economic order quantity • Number of units to order to minimise costs
EOQ
2
CoD Ch
Given in Exam
Slide 40
Discounts • Available above a certain order quantity • Is it worth ordering above the EOQ to get the discount? • Steps: – Calculate EOQ – Recalculate EOQ if it falls within a discount band – Calculate total costs at EOQ – Calculate total costs at the lower boundary of each discount band Slide 41
Economic batch quantity • Used when stock replenished gradually – internally or; – from supplier
• Similar to EOQ but factors in replenishment rate • Total EBQ never held in stock – as stock is being replenished during the period
Slide 42
Economic batch quantity EBQ
2CoD
Ch 1
D R
Total holding costs in period
Total set up costs in period
Slide 43
Given in Exam
Q 1 2
D Q
D Ch R
Co
Chapter 7
Study Text Chapter 7
Labour costs
Method of remuneration • Time-based systems
• Piecework systems
• Bonus/incentive schemes Slide 45
Measuring labour activity • Productivity • Standard hours of production • Efficiency x capacity = production volume
Slide 46
Accounting for labour costs • Direct or Indirect labour – learn the rules • Ledger accounting – Dr Wages account Gross wages – Cr Bank / PAYE / NIC accounts
Slide 47
– Dr WIP account – Cr Wages account
Direct wages Direct wages
– Dr Production o/h – Cr Wages account
Indirect wages Indirect wages
Labour turnover • The rate at which employees leave the company • Reasons may be controllable or uncontrollable by the company
Slide 48
Chapter 8
Study Text Chapter 8
Overheads and absorption costing
Cost card •
Aim
–
to find the full cost of one unit
$/unit Direct materials 4kg @ $2/kg Direct labour 3 hrs @ $7/hr Primceost
X X
Overheads FullProductcost
Slide 50
Allocate
X X X
3 Steps
Absorption costing method Total Production Costs Direct Costs
Indirect Costs (overheads)
1.Allocate & Apportion
COST CENTRES
Allocate
Production 1
Production 2
Service
Production 1
Production 2
2.Reapportion
3. Absorb
COST UNIT Slide 51
Overheads – step 1 Total Production Costs Direct Costs
Indirect Costs (overheads)
1.Allocate & Apportion
COST CENTRES
Allocate
Production 1
COST UNITS Slide 52
Production 2
Service
Overheads – step 2 Total Production Costs Direct Costs
Indirect Costs (overheads)
1.Allocate & Apportion
COST CENTRES
Allocate
Production 1
Production 2
Service
Production 1
Production 2
2.Reapportion
COST UNITS Slide 53
Reapportionment To reapportion service cost centre overheads to production cost centres there are 2 methods Direct Method
Inter-service department work is ignored Slide 54
Reciprocal Method
All inter-service department work is recognised
Overheads – step 3 Total Production Costs Direct Costs
Indirect Costs (overheads)
1.Allocate & Apportion
COST CENTRES
Allocate
Production 1
Production 2
Service
Production 1
Production 2
2.Reapportion
3. Absorb
COST UNIT Slide 55
3. Absorb The final step is to charge these overheads to cost units. This is called absorption. Production overhead OAR (overhead absorption rate) =
_______________ Activity level
What activity level should you use?
Slide 56
3. Absorption bases (a)Perunit
OAR/unit
(b)Perlabourhr
OAR/labhr
(c) Per machine hr
OAR/mach hr
(d) % Direct Labour cost
OAR/$ labour
(e) % Direct material cost
OAR/$ mats
(f) % Prime cost Slide 57
OAR/$ prime cost
Pre-determined OARs Businesses estimate (or pre-determine) their OAR at the start of the year OAR =
Production Overhead __________________ Activity level
BECOMES….. Pre-determined OAR =
Budgeted overhead _________________ Budgeted activity level
Slide 58
Cont. Businesses want to record overheads regularly during the year
Overhead = Actual Activity (eg labour hrs) Absorbed
Slide 59
x
Pre-determined OAR
Cont. At the end of the year actual overheads will be known
Overhead Absorbed
Actual Overhead
Difference = under or over absorption
Slide 60
Reasons for under/over absorption Why do we get an under or over absorption? Budgeted overhead Pre-determined = _________________ OAR Budgeted activity level
Budgeted overhead Actual overhead Expenditure variance Slide 61
Budgeted activity Actual activity Volume variance
Non production overheads • For internal reporting non-production overheads can also be allocated to units • One approach may be:
OAR =
Non-Production Overhead Production overhead
Slide 62
X 100
Chapter 9
Study Text Chapter 9
Marginal and absorption costing
Cost card – marginal costing $/unit
Slide 64
Directmaterials
X
Directlabour
X
Variable overhead Marginalcost
X X
Used to value stock under Marginal costing
Fixedoverheads
X
Full product cost
X
Used to value stock under Absorption costing
Contribution Contribution = selling price less ALL variable costs
$ Selling price Less: Variable production costs Variable non-production costs Contribution
Slide 65
X X X (X) X
Marginal costing profit statement
$ X
Sales Cost of sales
Opening Stock
(@ Marginal cost)
Production costs: Variable costs (mats, lab, var.overhead) Closing Stock
(@ Marginal cost)
X X (X) _____ (X)
Variable non production costs Contribution
(X) ____ X
Less: Fixed costs
(X) ____
P Nreotfit Slide 66
X
Absorption costing profit statement
$ X
Sales Cost of sales
Opening Stock
(@ Full cost)
Production costs: Variable costs (mats, lab, var.overhead) Fixedoverheadsabsorbed
X X X
Closing Stock (@ Full cost) (X) Overhead = Actual Activity X OAR Adjustment X/(X) Absorbed for under/(over) absorption _____ (X) ____ GroP srsofit X Non production costs (sales, distribution, admin) ____ X P Nreotfit Slide 67
X
Reconciliation proforma Year1 $
Absorption costing profit Add: Fixed overhead in opening stock Less: Fixed overhead in Closing stock = Marginal costing profit
Slide 68
Year2 $
Reconciling profits Difference in profit
= Change in stock
X
OAR/unit
But which profit is higher AC profit Or MC Profit? Production Closing stock AC Profit Slide 69
> = < > < = > < =
Sales Opening stock MC Profit
Chapter 10
Study Text Chapter 10
Process Costing
Introductory example – a party • a barrel holds 100 pints of beer and costs $100 much we • How charge per should pint to cover our costs?
$100 = $1/pint 100 pints Slide 71
However…… Will you get the full 100 pints from your barrel?? We only actually expect to get 95 pints
Normal loss = 5 pints So… what should we charge now per pint?
$100 = $1.05/pint 95 pints Slide 72
Normal loss – eg barrel dregs! What could we do with our loss? A local gardener likes the dregs for his plants – he‟ll pay 20p per pint, we could use this to reduce our costs. So… what should we charge now per pint?
x 5value pints) - scrap $100 - (20¢ = $1.04/pint 95 pints Slide 73
Cont. So how have we found the cost of a pint to charge our party goers? Cost per unit = Input costs - Scrap value of normal loss ________________________________ Input units - Normal loss units
Learn this formula! Slide 74
But…… What about unexpected losses?? At the end of the party we realise that we didn‟t get the 95 pints we expected we only got 85.
Abnormal loss = 10 pints Its too late to charge more, we have already charged $1.04 per pint….… …its just our loss we‟ll have to cover the $1.04 for each pint we didn‟t sell Slide 75
Finally….good news What if losses weren‟t as much as we expected? At the end of the party we realise that instead of the 95 pints we were expecting we actually got 98 pints from the barrel.
Abnormal gain = 3 pints We expected to scrap them for 20¢ – we actually sold them for $1.04 Slide 76
Normal Loss • Normal loss = expected loss Good output Inputs
Slide 77
Process 1
Normal loss
Abnormal loss or gain • Abnormal loss = unexpected loss • Abnormal gain = unexpected gain
Good output Inputs
Process 1
Normal loss Abnormal loss / gain
Slide 78
Recap – Process costing 1
Units calculation
2
Set up the process account and complete as far as possible
3
Calculate cost per unit:
4
Valuations & transfer to process account
Slide 79
Input units = Good output + NL +/(-) AL/(AG)
CPU = Input cost - scrap proceeds from normal loss Input units – normal loss units
Introduction to WIP Input costs - Scrap value of normal loss ________________________________ Cost per unit = Input units - Normal loss units
BUT….What if units aren‟t finished? MAY HAVE…..
Slide 80
Introduction to WIP
Finished unit
WIP units
We can‟t give them the same value Slide 81
Equivalent units Output from process includes:
½unit
+
½unit
+
1 whole unit
2 equivalent whole unit cost per equivalent unit Slide 82
Previous processes
Process I
Process II
• Process 1 is another input • OWIP 100% complete for Process 1
Slide 83
Summary and question approach 1
Units calculation
2
Set up the process account and complete as
3
far as possible Complete statement of equivalent units
4
Calculate cost per equivalent unit
5
Valuations & transfer to process account
Slide 84
Opening WIP + Input = Good output + NL +/(-) AL/(AG) + Closing WIP
Chapter 11
Study Text Chapter 11
Process costing, joint products and by-products
Joint products and by-products
Joint products
forestry By product Slide 86
Joint products and by-products Product 1
Inputs
Process (Joint costs)
Separation point
Slide 87
Product 2
By-product
Joint products and by-products - accounting
Joint products Substantial sales value
• Apportion joint costs – Various methods: as specified in question
Slide 88
By-products Relatively low sales value Secondary to process • Do not allocate costs – USUAL occurrence: reduce process costs – ONE-OFF: misc income
Chapter 12
Study Text Chapter 12
Job, batch and service costing
Job and batch costing • Job = a cost unit of a single order/contract • Batch = a cost unit which consists of a separate, readily identifiable group of units
Slide 90
Job cost cards Job XYZ $ Direct materials
X
Direct labour (hrs @ $/hr) Variable overheads (hrs @ $/hr) Prim coest
X X X
Fixed overheads Tocto alst
X X
Profit Sellingpriceojfob
Slide 91
X X
Cost structures If profit is 20% of cost
If profit is 20% of sales price
Selling price
120%
Selling price
100%
Costs
100%
Costs
80%
Profit
20%
Profit
20%
MARK - UP Slide 92
MARGIN
What are service organisations? • Don‟t make or sell a tangible product • Profit making or not-for-profit sector Accountancy firms, hotels, schools, – E.g. hospitals
• Service costing v. other product costing – Cost of direct materials is small – Unit cost is difficult to calculate – Costing will vary from one service to another Slide 93
Cost per unit
Cost per unit =
Total costs for a period ______________________________ Number of service units in the period
But what is a service cost unit ?
Slide 94
Composite cost unit A composite cost unit takes into account several elements of a service e.g. excess baggage service Cost per KG? OR Cost per mile transported?
Cost per KG/mile Slide 95
Service department costing • Cost of an „internal service‟ • Purposes of service department costing – Control costs and efficiency – Prevent unnecessary use of services • What cost to charge to user dept – No charge – Total actual cost – Standard absorption cost – Variable cost – Opportunity cost – Cost plus a margin for profit Slide 96
Chapter 13
Study Text Chapter 13
Budgeting
Planning and control • Planning and control cycle Determine objectives
Control - variances
Planning
Actual operations
Slide 98
–
set budget
Preparation of budgets • Budget period • Budget manual • Budget committee
Slide 99
Fixed and flexible budgets • Fixed budget = Master (srcinal) budget – Prepared at the start of the budget period
• Flexible budget = „scenario planning‟ – Prepared at the start of the year – What if? analysis – Flexed budget is a flexible budget prepared at the end of the year using the actual volumes
Slide 100
Chapter 14
Study Text Chapter 14
Standard Costing
Standard Costing WHAT IS A STANDARD COST? • An estimated unit cost • For example: – Direct materials
3kg x $2/kg
$6
» Based on standard usage ie 3kg / unit » Based on standard cost / kg ie $2 / kg
Slide 102
Lecture example 1 • Ideal standard
perfect operating conditions
• Current standard
use last year
• Basic standard
leave unaltered over long period
• Expected standard
attainable improvements
Slide 103
Chapter 15
Study Text Chapter 15
Basic variance analysis
Variances
actual results
DIFFERENCES =
expected results
VARIANCES
Can be FAVOURABLE Slide 105
Variances
actual results
DIFFERENCES =
expected results
VARIANCES
Or ADVERSE Slide 106
Cost variances Materials usage variance
Materials price variance
Unit cost Direct Materials
3kg x $2 / kg
$6
Direct Labour
4hrs x $6 / hr
$24
Labour efficiency variance
Labour rate variance
Variable overheads 4hrs x $2 / hr Var o/h efficiency variance
Marginal cost Slide 107
$8
Var o/h expenditure variance
$38
Basic cost variances • For example: materials price variance – Actual purchases SHOULD cost
x
• Actual purchases x standard cost
– Actual puchases DID cost • Actual purchases x actual cost
Slide 108
x x
Basic cost variances • For example: Materials usage variance – Actual production SHOULD use
x kg
• Units produced x standard usage
– ActualproductionDIDuse • Units produced x actual usage
• Value at standard cost / kg
Slide 109
xk g x kg $x
Fixed overhead variances Fixed overheads Total variance Expenditure variance
Volume variance Efficiency variance
Slide 110
Over/underabsorption
Capacity variance
Causes of variances • C ontrollable expenditure • A ccuracy – measurement of data • U ncontrollable expenditure • S tandard type • E xpectations – unrealistic standard
Slide 111
Interdependence of variances Variances may affect each other e.g. Cheaper materials Inferior quality
Slide 112
Favourable price variance Adverse usage variance (& labour efficiency?)
Interdependence of variances Variances may affect each other e.g. Increase in sales price Favourable price variance Fall in demand
Slide 113
Adverse sales volume variance
Chapter 16
Study Text Chapter 16
Further variance analysis
Operating statement MC Budgetedcontribution Sales volume variance Flexed budgeted contribution Sales price variance Variable cost variances Actual contribution Budgeted fixed o/h Fixed o/h expenditure variance Actual fixed o/h Actuparlofit
Slide 115
x x/(x) x x/(x) x/(x) x
x x/(x) (x) x
Differences between MC and AC For Absorption Costing: • Sales volume variance – Difference between budgeted sales and actual sales units valued at standard PROFIT per unit under AC
• Fixed overhead variances – Calculate a fixed overhead volume variance. This can also be split into an efficiency and capacity variance
• Operating statement – Reconcile between budgeted profit and actual profit Slide 116
Operating statement AC Budgetep drofit
x
Sales volume variance Flexedbudgetedprofit
x/(x) x
Sales price variance
x/(x)
Cost variances (including fixed overheads
x/(x)
Actup arl ofit
Slide 117
x
Chapter 17
Study Text Chapter 17
Cost-volume-profit Analysis
Introduction £ Sales Less:VCs
15,000 (5,000) _____
Contribution
10,000
Fixed ? costs
(10,000) ? _____ 0
Profit Slide 119
Must be EQUAL
Introduction So we will breakeven when… Contribution = Fixed costs Cont‟n/unit x Q = Fixed costs Fixed costs Q = __________ Cont‟n/unit
Slide 120
Breakeven Revenue – C/S Ratio In the last e.g. B/E Revenue = BEP x SP/unit Fixed costs x SP/unit B/E Revenue = __________ Cont‟n/unit B/E Revenue = Fixed costs x _________ Cont‟n/unit SP/unit _________ Cont‟n/unit SP/unit
Fixed costs __________ B/E Revenue C/S=ratio C/S ratio Slide 121
Margin of safety Margin of safety (in units) = Budgeted sales volume – breakeven sales volume
OR
Margin of safety (as %) = Budgeted sales volume – breakeven sales volume __________________________________________ X 100 Budgeted sales volume
Slide 122
Breakeven chart Total Revenue (TR)
TR = SP/unit x Q TR = $8/unit x Q if Q = 0, TR = 0 if Q = 5000, TR = 40,000 Slide 123
Breakeven chart Total Cost (TC)
TC = FC + VC/unit x Q TC = $5,700 + $6.50/unit x Q if Q = 0, TC = 5,700 if Q = 5000, TC = 38,200 Slide 124
Breakeven chart $ TR
40,000
Profit
TC
38,200 30,400
Fixed cost 3,800
5,000
Margin of safety Slide 125
Q
Profit volume chart Profit
$1,800
$0
3,800
5,000
Margin of safety ($5,700)
Slide 126
Q
Required profit level Fixed Fixed costscosts + required profit Sales volume to reach ______________________ ______________ Breakeven point = required profit level Contribution/unit
Slide 127
Chapter 18
Study Text Chapter 18
Relevant costs and decision making
Relevant Costs • What is a relevant cost?
FUTURE
Only future costs are affected by our decision Slide 129
INCREMENTAL
i.e. incurred as a direct result of our decision
CASHFLOW
Only cash
Popular scenario with examiner
e.g. need 500kg of material for new project have 300kg in stock (cost $3/kg) current purchase price = $5/kg scrap value = $1/kg
what‟s the relevant cost of the 500kg? Slide 130
Relevant cost - materials Instock In continual use
No other use
Notinstock
Scarce
Just have to buy it Relevant
If take from stock will have to replace
If take from stock won’t have to replace
If take from stock can’t replace
Relevant cost = current purchase price
Relevant cost = scrap value foregone
Relevant cost = opportunity cost
Slide 131
cost = current purchase price
Relevant cost - labour labour Could hire more
Spare capacity
Full capacity
Relevant cost = current rate of pay
Relevant cost = nil
Relevant cost = opportunity cost
Slide 132
Relevant cost - labour Full capacity
E.g. labour is currently working on product A Product A Lose $ $ Sales revenue 50 Lose revenue 50 Materials (3) Save materials (3) Labour (1hr) Labour (1hr) (5) _____ _____ Contribution Loss to business 47 42 What do we lose if we take the labour away to work on a new product – B? Slide 133
Relevant cost
Relevant cost - labour Full capacity
E.g. labour is currently working on product A Alternative calc. Product A $ $ Sales revenue 50 Lost cont‟n 42 Materials (3) Add back labour 5 _____ Labour (1hr) (5) _____ Loss to business 47 Contribution 42 Relevant cost Slide 134
Deprival value • How to find the relevant cost of an asset Lower of..
Replacement cost
Higher of..
Net realisable value Slide 135
Value in use
Single limiting factor analysis 1
Identify limiting factor
2
Calculate contribution per unit
3
Calculate contribution per limiting factor
4
Rank products
5
Prepare a production plan
Slide 136
Chapter 19
Study Text Chapter 19
Linear programming
Limited resources • A business needs to identify the optimal production plan for utilising its resources to maximise profit • 2 techniques – Single limiting factor – Linear programming (>1 limiting factor)
Slide 138
Example A business manufactures 2 products – garden gnomes and garden statues. Information for one unit of each product is given below: Gnome
Statue
Contribution
$6
$9
Material
2kg
4kg
Labour
5 hours
6 hours
There are only 80 kg of material available and 180 hours of labour. Demand for the statues will not be above 10 units per week.
Slide 139
Linear programming steps
1
Define variables
– let g = number of gnomes produced per week – let s = number of statues produced per week – let k = contribution per week
Slide 140
Linear programming steps 2
Establish constraints
– subject to: • Materials • Labour
2g+4s 80 5g + 6s 180
• Demand • Non-negativity
s 10 g,s > 0
3
Formulate objective function
– Max k = 6g + 9s
Slide 141
Linear programming steps 4
Plot constraints on graph
– Find co-ordinates • Materials
2g+4s=80 When g=0, s=20 s=0, g= 40
• Labour
5g+6s=180 When g=0, s= 30 s=0, g=36
• Demand • Non-negativity
Slide 142
s = 10 g,s > 0
Linear programming steps
s
Materials: 2g + 4s = 80
30
Labour: 5g + 6s = 180 Demand : s = 10
20
10
0 Slide 143
10
20
30
40
g
Linear programming steps 5
Identify feasible region
s
Materials: 2g + 4s
30
Labour: 5g + 6s Demand : s
80 180
10
20
10
B
C D
A 0 Slide 144
10
20
30
E
40
g
Linear programming steps
6
Plot objective function and identify optimal point
k = 6g + 9s Pick any value for k • Say k = 6 x 9 = 54 • k = 54 = 6g + 9s – When g=0, s=6 – When s=0, g=9
Slide 145
Linear programming steps
s
Materials: 2g + 4s
30
Labour: 5g + 6s Demand : s
80 180
10
k = 6g + 9s
20
Optimal point = D 10
B
C D
A 0 Slide 146
10
20
30
E
40
g
Linear programming steps 7
Solve using simultaneous equations
Materials Labour
2g + 4s = 80 5g + 6s = 180
(i) (ii)
Rearrange (i) to get g on own Materials
g = 40 – 2s
Substitute in (ii) Labour 5g + 6s = 180 (ii) 5(40 – 2s) + 6s = 180 200 – 10s + 6s = 180 200 – 180 = 4s Slide 147
s=5
Linear programming steps Substitute s = 5 in (i) Materials 2g + 4s = 80 (i) 2g + (4 x 5) = 80 2g = 80 – 20 g = 30 Optimal production plan: 30 Gnomes 5 Statues Contribution: k = 6g + 9s k = (6 x 30) + (9 x 5) = £225 Slide 148