《宏观经济学原理》ch10

Investment,Saving,andtheRealInterestRateCHAPTER10CHECKPOINTSProblem1Problem2Problem1Problem2Problem1Problem2Problem3Problem3Checkpoint10.1Checkpoint10.2Checkpoint10.3ClickerversionPracticeProblem1

MichaelisanInternetserviceprovider.OnDecember31,2007,heboughtanexistingbusinesswithserversandabuildingworth$400,000.Duringhisfirstyearofoperation,hisbusinessgrewandheboughtnewserversfor$500,000.Themarketvalueofsomeofhisolderserversfellby$100,000.WhatwasMichael’sgrossinvestment,depreciation,andnetinvestmentduring2008andwhatisMichael’scapitalattheendof2008?CHECKPOINT10.1SolutionMichael’sgrossinvestmentduring2008was$500,000—themarketvalueofthenewservershebought.Michael’sdepreciationduring2008was$100,000—thefallinthemarketvalueofsomeofhisolderservers.Michael’snetinvestmentduring2008was$400,000.Netinvestmentequalsgrossinvestmentminusdepreciation,whichis($500,000$100,000).CHECKPOINT10.1Thecapitalgrewduring2008bytheamountofnetinvestment.Michael’snetinvestmentduring2008was$400,000.Sothatattheendof2008,capitalwas

$400,000+$400,000,whichequals$800,000.CHECKPOINT10.1PracticeProblem2Loriearns$20,000afterpayinghertaxes.Atthebeginningof2007,Loriowned$1,000worthofbooks,CDs,andgolfclubsandshehad$5,000inasavingsaccountatthebank.During2007,theinterestonhersavingsaccountwas$300andshespent$15,300onconsumptiongoods.Themarketvaluesofherbooks,CDs,andgolfclubsdidnotchange.HowmuchdidLorisavein2007?Whatwasherwealthattheendof2007?CHECKPOINT10.1SolutionLorisaved$5,000.Savingequalsincome(aftertax)minustheamountspent.Thatis,Lori’ssavingequaled$20,300minus$15,300,whichis$5,000.Lori’swealthattheendof2007was$11,000—thesumofherwealthatthestartof2007($6,000)plushersavingduring2007($5,000).CHECKPOINT10.1PracticeProblem1FirstCall,Inc.isacellularphonecompany.Itplanstobuildanassemblyplantthatcosts$10millioniftherealinterestrateis6percentayear.Iftherealinterestrateis5percentayear,FirstCallwillbuildalargerplantthatcosts$12million.Andiftherealinterestrateis7percentayear,FirstCallwillbuildasmallerplantthatcosts$8million.DrawagraphofFirstCall’sdemandforloanablefundscurve.CHECKPOINT10.2SolutionThedemandforloanablefundscurveisthebluedownward-slopingcurveDLF0andpassesthroughthepointshighlightedinthefigure.CHECKPOINT10.2PracticeProblem2FirstCall,Inc.isacellularphonecompany.Thegraphshowsitsdemandforloanablefunds.FirstCallexpectsitsprofittodoublenextyear.Ifotherthingsremainthesame,explainhowthisincreaseinexpectedprofitinfluencesFirstCall’sdemandforloanablefunds.CHECKPOINT10.2SolutionAnincreaseintheexpectedprofitincreasesinvestmenttoday,whichincreasesthequantityofloanablefundsdemandedateachrealinterestrate.ThedemandforloanablefundscurveshiftsrightwardtoDLF1inthefigure.CHECKPOINT10.2StudyPlanProblemFirstCall,Inc.expectsitsprofittodoublenextyear.Ifotherthingsremainthesame,FirstCall_________.A.increasesthequantityoffundsdemandedalongits demandforloanablecurve.B. decreasesitsdemandforloanablefundsC. increasesitsdemandforloanablefundsD. decreasesthequantityoffundsdemandedalongits demandforloanablecurveCHECKPOINT10.2PracticeProblem3Drawagraphthatillustrateshowanincreaseinthesupplyofloanablefundsandadecreaseinthedemandforloanablefundscanlowertherealinterestrateandleavetheequilibriumquantityofloanablefundsunchanged.CHECKPOINT10.2SolutionTheincreaseinthesupplyofloanablefundsshiftsthesupplycurverightward.Thedecreaseinthedemandforloanablefundsshiftsthedemandcurveleftward.Therealinterestratefalls.Iftheshiftsareofthesamemagnitude,theequilibriumquantityoffundsremainsunchanged.CHECKPOINT10.2PracticeProblem1Thetableshowsthedemandforloanablefundsscheduleandtheprivatesupplyofloanablefundsschedule.Ifthegovernmentbudgetsurplusis$1trillion,whataretherealinterestrate,thequantityofinvestment,andthequantityofprivatesaving?Isthereanycrowdingout?CHECKPOINT10.3SolutionWithagovernmentbudgetsurplusof$1trillion,thetotalsupplyofloanablefundscurveSLF.Theequilibriumrealinterestrateis6percentayearandthequantityofloanablefundsis$7.5trillion.Investmentis$7.5trillionandprivatesavingis$6.5trillion.Crowdingoutdoesnotoccur.CHECKPOINT10.3PracticeProblem2Thetableshowsthedemandforloanablefundsscheduleandtheprivatesupplyofloanablefundsschedule.Ifthegovernmentbudgetdeficitis$1trillion,whataretherealinterestrate,thequantityofinvestment,andthequantityofprivatesaving?Isthereanycrowdingout?CHECKPOINT10.3SolutionWithagovernmentbudgetdeficit

of$1trillion,thetotalsupplyofloanablefundscurveSLF.Therealinterestrateis8percentayear,investmentis$6.5trillion,andprivatesavingis$7.5trillion.Crowdingoutoccursbecausethedeficitraisestherealinterestrate,whichdecreasesinvestment.CHECKPOINT10.3Pract