中级微观经济学课件与习题考试题目2nd turorial class

IntermediateMicroeconomicsTestA(Chapter5-7)

Name: StudentID: Class:

Number

1

2

3

4

5

6

7

8

Answer

F

F

T

B

E

D

E

C

PartA:TrueorFalse(10*3)

MaxGrosshastheutilityfunctionU(x,y)=max{x,y}.Ifthepriceofxisthesameasthepriceofy,Maxwillbuyequalamountsofxandy.

Whenothervariablesareheldfixed,thedemandforaGiffengoodriseswhen eincreases.

RudolfRationalobeystheweakaxiomofrevealedpreferences.Hispreferencesdon'tchangeovertime.Oneyearhecouldaffordbundlexbutboughtbundley.Ifanotheryearhebuysbundlex,thenhecan'taffordbundley.

PartB:(14*5)

Hanshas$27whichhedecidestospendonxandy.Commodityxcosts$16perunitandcommodityycosts$10perunit.HehastheutilityfunctionU(x,y)=5x2+2y2andhecanpurchasefractionalunitsofxandy.Hanswillchoose

onlyx.

onlyy.

someofeachcommoditybutmoreythanx.

someofeachcommoditybutmorexthany.

equalamountsofthetwocommodities.

Harryhas$10tospendoncansofCokeandPepsi,whichheregardsasperfectsubstitutes,oneforone.Pepsicosts$.50acanandCokecosts$.60acan.Harryhas20coupons,eachofwhichcanbeusedtobuy1canofCokefor$.40.WhichofthefollowingbundleswillHarrybuy?

A．20cansofPepsiandnoCoke

B．162/3cansofCokeandnoPepsi

C．10cansofCokeand8cansofPepsi

D．10cansofCokeand12cansofPepsiE．Noneoftheabove.

Clarissa'sutilityfunctionisU(r,z)=z+120r-r2,whereristhenumberofrosentsshehasinhergardenandzisthenumberofzinnias.Shehas250squarefeettoallocatetorosesandzinnias.Roseseachtakeup4squarefeetandzinniaseachtakeup1squarefoot.Shegetsthentsforfromagenerousfriend.Ifsheacquiresanother100squarefeetoflandforhergardenandherutilityfunctionremainsunchanged,shewillnt

99morezinniasandsomemoreroses.

20morerosesand20morezinnias.

25morerosesandnomorezinnias.

100morezinniasandnomoreroses.

Noneoftheabove.

LetAstandforthebundle(7,9),Bstandforthebundle(10,5),andCstandforthebundle(6,6).Whenpricesare(2,4),BettychoosesC.Whenpricesare(12,3)shechoosesA.

AisdirectlyrevealedpreferredtoB

AisindirectlyrevealedpreferredtoB.

CisdirectlyrevealedpreferredtoA.

BisdirectlyrevealedpreferredtoA.

Noneoftheabove.

Whenpricesare($4,$2),Tomokochoosesthebundle(9,18),andwhenpricesare($1,$2),shechoosesthebundle(8,14).

Thebundle(8,14)isrevealedpreferredtothebundle(9,18)andshedoesnotviolateWARP.

SheviolatesSARPbutnotWARP.

Thebundle(9,18)isrevealedpreferredtothebundle(8,14)andshedoesnotviolateWARP.

SheviolatesWARP.

Noneoftheabove.

IntermediateMicroeconomicsTestB(Chapter5-7)

Name: StudentID: Class:

Number

1

2

3

4

5

6

7

8

Answer

T

F

F

E

B

C

A

B

PartA:TrueorFalse(10*3)

Millie'sutilityfunctionisU(x,y)=min{x,y}.Sheizesherutilitysubjecttoabudgetconstraint.Thepriceofxisthesameasthepriceofy.Ifthepriceofxrisesandthepriceofyandher eremainconstant,thenherconsumptionofywillcertainlydecrease.

Patiencewasizingherutilitysubjecttoherbudgetconstraint.PriceschangedandPatiencewaslesswelloffthanbefore.Therefore,attheoldpriceshernewbundlemustcostlessthanheroldbundle.

Donald'sutilityfunctionisU(x,y)=x+y1/2.Currentlyheisbuyingsomeofbothgoods.Ifhiserisesandpricesdon'tchange,hewillbuymoreofbothgoods.

PartB:(14*5)

WandaLittlemore'sutilityfunctionisU(x,y)=x+46y-2y2.Her eis$135.Ifthepriceofxis$1andthepriceofyis$18,howmanyunitsofgoodxwillWandademand?

5

12

16

0

9

PartB:(14*5)

Form>p2,thedemandfunctionsforgoods1and2aregivenbytheequations,x1=m/p2-1andx2=p1/p2,wheremis eandp1andp2areprices.Letthehorizontalaxisrepresentthetyofgood1.Letp1=1andp2=2.Thenform>2,the eoffercurveis

A．averticalline.

．ahorizontalline.

C．astraightlinewithslope2.

D．astraightlinewithaslopeof1/2.E．Noneoftheabove.

CokeandPepsiareperfectsubstitutesforMr.Drinkerandtheslopeofhisindifferencecurvesisminus1.Onedayhebought2cansofCokeand20cansofPepsi.(Thecansofbothdrinksarethesamesize.)

CokeislessexpensivethanPepsi.

CokeismoreexpensivethanPepsi.

CokeandPepsicostthesame.

Mr.DrinkerprefersPepsitoCoke.

Noneoftheabove.

7.Isobelconsumespositive tiesofbothjamandjuice.Thepriceofjamis5centsper

unitandthepriceofjuiceis10centsperunit.Hermarginalutilityofjamis10andhermarginalutilityofjuiceis5.

Withoutchanginghertotalexpenditures,shecouldincreaseherutilitybyconsumingmorejamandlessjuice.

Withoutchanginghertotalexpenditures,shecouldincreaseherutilitybyconsumingmorejuiceandlessjam.

Withoutchanginghertotalexpendituresonjamandjuice,shecouldnotincreaseherutility.Sheshouldspendmoremoneyonbothjamandjuice.

Wecan'tlwhetheranyoftheotherstatementsaretrueorfalsewithoutknowingthetiessheconsumes.

Twentyyearsago,Dimitriconsumedbreadwhichcosthim10kopeksaloafandpotatoeswhichcosthim20kopeksasack.Withhis eof330kopeks,hebought9loavesofbreadand12sacksofpotatoes.Todayhehasan eof452kopeks.Breadnowcostshim22kopeksaloafandpotatoescosthim17kopeksasack.Assuminghispreferenceshaven'tchanged(andthesizesofloavesandsackshaven'tchanged),whenwashebetteroff?

Hewasbetteroff20yearsago.

Heisbetterofftoday.

Hewasequallywelloffinthetwoperiods.

Fromtheinformationgivenhere,weareunabletol.

Noneoftheabove.

Somesupplementaryknowledge:

Convexity(凸性):Mixturesofbundlesare(atleastweakly)preferredtothebundlesthemselves.MRS= fromconvexutilityfunction,whenxisincreasing,MRS

(negative)isalsoincreasing.Non-convexfunctionhascornersolution,sobeforeyoucalculateinteriorsolution,checkconvexityfirst.

Homotheticpreference:

(x1,x2)>(y1,y2) (kx1,kx2)>(ky1,y