Here are the graphs for each scenario: 1. Decreased demand for maize due to health concerns: [GRAPH 1] 2. Increased demand for maize as a complement to barbecues: [GRAPH 2] 3. Increased demand for maize due to higher household income: [GRAPH 3]

1. Mohr & Fourie: Chapter / Hoofstuk 7
ECON111_2011

2. Introduction Inleiding

3. Outcomes Uitkomstes
 Discuss & apply ...  Bespreek & pas toe...
 Determinants of DEMAND  Determinante van VRAAG
 Determinants of SUPPLY  Determinante van AANBOD
 Illustrate DEMAND & SUPPLY in ...  Illustreer VRAAG & AANBOD in
 Words  Woorde
 Symbols  Syfers
 Graphs  Grafieke
 Equations  Vergelykings
 Illustrate / calculate EQUILIBRIUM  Illustreer / bereken EWEWIG
 Differentiate between ...  Onderskei tussen ...
 DEMAND vs. QUANTITY demanded  VRAAG vs.HOEVEELHEID gevra
 Individual DEMAND vs. Market  Individuele VRAAG vs. Mark VRAAG
DEMAND  AANBOD vs. HOEVEELHEID
 SUPPLY vs. QUANTITY supplied aangebied
 Individual SUPPLY vs. Market SUPPLY  Individuele AANBOD vs. Mark
 Movement ALONG/ON curve vs. AANBOD
Movement OF THE curve  Beweging LANGS/OP kromme vs.
 Discuss, calculate, illustrate Beweging VAN DIE kromme
 Producer Surplus  Bespreek, bereken, illustreer
 Consumer Surplus  Produsente Surplus
 Verbruikers Surplus

4. Mohr & Fourie: Chapter / Hoofstuk 7
ECON111_2011

5. Outcomes Uitkomstes
 Discuss & apply ...  Bespreek & pas toe...
 Determinants of DEMAND  Determinante van VRAAG
 Illustrate DEMAND in ...  Illustreer VRAAG in
 Words  Woorde
 Symbols  Syfers
 Graphs  Grafieke
 Equations  Vergelykings
 Differentiate between ...  Onderskei tussen ...
 DEMAND vs. QUANTITY  VRAAG vs.HOEVEELHEID
demanded gevra
 Individual DEMAND vs. Market  Individuele VRAAG vs. Mark
DEMAND VRAAG
 Movement ALONG/ON curve  Beweging LANGS/OP kromme
vs. Movement OF THE curve vs. Beweging VAN DIE kromme

6. What is (effective) DEMAND? Wat is (effektiewe) VRAAG?
 Definition ...  Definisie ...
 Want to ...  Wil ...
 Able to ...  Kan ...
 Referring to the quantities  Verwys na die hoeveelheid
of a good or service that van ’n produk of diens wat
the potential buyers are die potensiële kopers kan
willing and able to buy. bekostig om aan te koop
en bereid is om aan te
koop.
 Two types
 Individual
 Market  Twee tipes
 Individueel
 Mark

7. I and M DEMAND? I en M VRAAG?
(P) Sam Zena Zeb
Totaal /
SS Pie Total
1 6 4 5 15
2 5 3 4 12
3 4 2 3 9
4 3 1 2 6
5 2 0 1 3
Illustrate Sam’s individual demand Illustreer Sam se individuele vraag
curve for SS pies. kromme vir SS “pies”.
Illustrate market demand Illustreer mark vraag.

8. What does DEMAND look like? Hoe lyk VRAAG?
 Schedule / Table 7-1  Skedule / Tabel 7-1
Price / kg Qd Prys / kg Qd
1 6 1 6
2 5 2 5
3 4 3 4
4 3 4 3
5 2 5 2
 Remember the Equation  Onthou die Vergelyking
 Y = c + mX  Y = c + mX
 ECONOMICS  EKONOMIE
 Pd = a + bQd  Pd = a + bQd
REWRITE: REWRITE:
Qd = a – Pd
Qd = a – P d
b
b

9. TIP: Y = a + bX TIP: Y = a + bX
 Y is replaced by P  Y word met P vervang
 X is replaced by Q  X word met Q vervang
Pd = a + bQd Pd = a + bQd
 Solve (b) first  Begin met (b)
 Slope = b  Helling = b
  in Y over  in X   in Y oor  in X
 THUS P / Q
 (Dus P/ Q)
 Then solve (a)  Bereken dan (a)
 Replace P, Q, b (P, Q from table)  Vervang P, Q, b (P, Q vanuit tabel)
 P = a +bQ  In P = a + bQ
 Solve for a:
 Los op vir (a) = P + bQ
 a = P + bQ

10. CLASS WORK KLASWERK
Qd 0 1 2 3 4 5 6 7 8 9 10 11 12
P 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 1.5 0
By making use of the table, determine Lei die vraag vergelyking af deur
the demand equation. gebruik te maak van die bostaande
tabel.

11. CLASS WORK KLASWERK
Qd 0 1 2 3 4 5 6 7 8 9 10 11 12
P 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 1.5 0
STEP 0: Y = c + mX
STEP 1: Pd = a + bQd
STEP 2: b (Slope / Helling)
= P/ Q
= 5.5 – 6
1–0
= -0.5
STEP 3: a (Intercept/Afsnit)
= 6
STEP 4: Pd = a – bQd
Pd = 6 – 0.5Qd

12. CLASS WORK KLASWERK
Qd 0 1 2 3 4 5 6 7 8 9 10 11 12
P 6 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 1.5 0
STEP 5: REWRITE FOR Qd
Pd = 6 – 0.5Qd
0.5Qd = 6 – Pd
Qd = 6 – Pd
0.5
Qd = 12 – 2Pd

13. DEMAND VRAAG
 With Demand two things  Met vraag kan twee goed
can happen... gebeur...
 Movement ALONG/ON  Beweging LANGS/OP die
the curve kromme
 Movement OF the curve  Beweging VAN die kromme

14. MOVEMENT BEWEGING
ON OP
WHEN? WANNEER?
PRICE (GOOD / PRYS
SERVICE) (GOEDERE /
CHANGE DIENS)
VERANDER

15.  QUANTITY demanded  HOEVEELHEID gevra
 Change in QUANTITY demanded  Verandering in HOEVEELHEID
(Qd) gevra (Qd)
 DEMAND (DD) unchanged  VRAAG (DD) bly staan
 1 curve  1 kromme
 NB. caused by  PRICE  NB. a.g.v.  PRYS
P
Qd Qd

16. Movement ON curve Beweging OP kromme
 ONE DEMAND curve  EEN VRAAG kromme
 Verandering in HOEVEELHEID
 Change in QUANTITY demanded
gevra (Qd)
(Qd)
 NIE verandering in VRAAG nie (D)
 NOT a change in DEMAND (D)
P
Qd QD 

17. MOVEMENT BEWEGING
OF VAN
WHEN? WANNEER?
PPPINT PPPINT

18. What determines DEMAND? Wat veroorsaak VRAAG?
 5 Determinants of  5 Determinante van
INDIVIDUAL demand INDIVIDUELE vraag
 PPPINT  PPPINT
 Qd = f(PPPINT...)  Qd = f(PPPINT...)

19.  DEMAND  VRAAG
 Change in DEMAND (D)  Verandering in VRAAG (D)
 DEMAND (DD) shifts/moves  VRAAG (DD) skuif
 2 curves  2 krommes
 NB. NOT product PRICE  NB. NIE produk PRYS NIE
IF DEMAND  AS VRAAG 
YOU WILL SKUIF JY DIE
SHIFT THE VRAAG
DEMAND KROMME NA
CURVE TO REGS
THE RIGHT
AS VRAAG 
IF DEMAND  SKUIF JY DIE
YOU WILL VRAAG
SHIFT THE D KROMME NA
DEMAND LINKS
CURVE TO
THE LEFT

20.  DEMAND  VRAAG
Regs
Right
Links
Left

21. PRICE OF PRYS VAN
SUBSTITUTE SUBSTITUUT
P
P
Qd 
Qd 

22. PRICE OF PRYS VAN
COMPLEMENTS KOMPLIMENT
P
D1
D2
P
Qd 
Qd 

23. PRICEe PRYSe
P
P Jan. 2012
In Jan. 2012
D2
D1
P
Qd

Qd 

24. INCOME INKOME
Your income 
As jou inkome ... Wat
gebeur met jou vraag?
If income increases...
What will happen to
your demand?
Qd 

25. Population Bevolking
Hoe groter die bevolking...
Hoe groter is die vraag na die
produk/diens
Die vraag na brood in SA gaan
hoer wees as die vraag na
brood in die Seychelles.
Qd 

26. TASTE VOORKEURE
1) Levis jeans is last season... This season Guess
D1 D2
D1
D2 D1
D2
Qd  Qd 

27. TABEL / TABLE 7.3
!

28. Homework 1 Homework 1
 Consider the demand for  Die sokker Wêreldbeker
tickets to the World Cup finaal word in 2010 in Suid-
final, to be held in 2010. Afrika gehou. Gestel die
Imagine that the planners of FIFA beplanners het geskat
the World Cup estimate that dat die vraag na kaartjies vir
the demand for tickets for die eindwedstryd voorgestel
the final game can be kan word deur:
represented as follows: QD = 500 000 – 500 P
QD = 500 000 – 500 P

29. QD = 500 000 – 500 P QD = 500 000 – 500 P
On the basis of this information, please Met hierdie inligting, voltooi die volgende
complete the following demand schedule vraagskedule
Prys / Price Hoeveelheid gevra /
(P) Quantity demanded (QD)
0
100
200
300
400
500
600
700
800
900
1000

30. HOMEWORK 2 HUISWERK 2
 Consider the market of  Oorweeg die mark vir
maize in South Africa. Using mielies in Suid-Afrika in ag.
standard notions of demand Deur gebruik te maak van
what effect will the following die standaard neigings van
changes have, ceteris vraag, skets die effek wat
paribus. Make use of a die veranderinge sal
graph in each of your aanbring, ceteris paribus.
answers. Maak gebruik van ’n
grafiek in elk van u
antwoorde.

31. 1. Medical reports indicate 1. Mediese verslae toon dat ʼn
that a staple diet of maize stapel dieet van mielies
is nutritionally unbalanced ongebalanseerd is en
and people are encouraged mense word aangemoedig
to eat less maize. om minder mielies te eet.
2. It becomes popular to eat 2. Om mieliepap saam met
mieliepap at a barbeque. braaivleis te eet word
3. The average income of gewild.
households increase. 3. Die gemiddelde inkomste
van huishoudings styg