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1、SOLUTIONSTOTEXTPROBLEMS: QuickQuizzes 1. Amarketmighthaveamonopolybecause:⑴akeyresourceisownedbyasinglefirm;(2)thegovernmentgivesasinglefirmtheexclusiverighttoproducesomegood;and(3)thecostsofproductionmakeasingleproducermoreefficientthanalargenumberofproducers. Examplesofmonopoliesinclude:⑴thewat

2、erproducerinasmalltown,whichownsakey resource,theonewellintown;(2)pharmaceuticalcompanieswhoaregivenapatentonanewdrugbythegovernment;and(3)abridge,whichisanaturalmonopolybecause(ifthebridgeisuncongested)havingjustonebridgeisefficient.Manyotherexamplesarepossible. 2. Amonopolistchoosestheamountofou

3、tputtoproducebyfindingthequantityatwhichmarginalrevenueequalsmarginalcost.Itfindsthepricetochargebyfindingthepointonthedemandcurveatthatquantity. 3. Amonopolistproducesaquantityofoutputthat'slessthanthequantityofoutputthatmaximizes totalsurplusbecauseitproducesthequantityatwhichmarginalcostequalsm

4、arginalrevenueratherthanthequantityatwhichmarginalcostequalsprice. 4. Policymakerscanrespondtotheinefficienciescausedbymonopoliesinoneoffourways:⑴by tryingtomakemonopolizedindustriesmorecompetitive;(2)byregulatingthebehaviorofthemonopolies;(3)byturningsomeprivatemonopoliesintopublicenterprises;and

5、(4)bydoingnothingatall.Antitrustlawsprohibitmergersoflargecompaniesandpreventthemfromcoordinatingtheiractivitiesinwaysthatmakemarketslesscompetitive,butsuchlawsmaykeepcompaniesfrommergingtogainfromsynergies.Somemonopolies,especiallynatural monopolies,areregulatedbythegovernment,butitishardtokeepamo

6、nopolyinbusiness,achievemarginal-costpricing,andgivethemonopolistincentivetoreducecosts.Private monopoliescanbetakenoverbythegovernment,butthecompaniesarenotlikelytobewellrun.Sometimesdoingnothingatallmayseemtobethebestsolution,butthereareclearlydeadweightlossesfrommonopolythatsocietywillhavetobear

7、. 5. Examplesofpricediscriminationinclude:(1)movietickets,forwhichchildrenandseniorcitizens getlowerprices;(2)airlineprices,whicharedifferentforbusinessandleisuretravelers;(3)discountcoupons,whichleadtodifferentpricesforpeoplewhovaluetheirtimeindifferentways; (4) financialaid,whichofferscollegetu

8、itionatlowerpricestopoorstudentsandhigherpricestowealthystudents;and(5)quantitydiscounts,whichofferlowerpricesforhigherquantities,capturingmoreofabuyer'swillingnesstoMpay.otherexamplesarepossible. Perfectpricediscriminationreducesconsumersurplus,increasesproducersurplusbythesameamount,andhasnoeffec

9、tontotalsurplus,comparedtoacompetitivemarket.Comparedtoa monopolythatchargesasingleprice,perfectpricediscriminationreducesconsumersurplus,increasesproducersurplus,andincreasestotalsurplus,sincethereisnodeadweightloss. QuestionsforReview 1. Anexampleofagovernment-createdmonopolycomesfromtheexisten

10、ceofpatentandcopyrightlaws.Bothallowfirmsorindividualstobemonopoliesforextendedperiodsoftime20yearsfor patents,foreverforcopyrights.Butthismonopolypowerisgood,becausewithoutit,noone wouldwriteabook(becauseanyonecouldprintcopiesofit,sotheauthorwouldgetnoincome)andnofirmwouldinvestinresearchanddevel

11、opmenttoinventnewproductsordrugs(sinceanyothercompanycouldproduceorsellthem,andthefirmwouldgetnoprofitfromitsinvestment). 2. Anindustryisanaturalmonopolywhenasinglefirmcansupplyagoodorservicetoanentiremarketatasmallercostthancouldtwoormorefirms.Asamarketgrowsitmayevolvefroma naturalmonopolytoacomp

12、etitivemarket. 3. Amonopolist'smarginalrevenueislessthanthepriceofitsproductbecause:(1)itsdemand curveisthemarketdemandcurve,so(2)toincreasetheamountsold,themonopolistmustlowerthepriceofitsgoodforeveryunititsells.(3)Thiscutinpricesreducesrevenueontheunitsitwasalreadyselling. Amonopolist'smarginal

13、revenuecanbenegativebecausetogetpurchaserstobuyanadditionalunitofthegood,thefirmmustreduceitspriceonallunitsofthegood.Thefactthatitsellsagreaterquantityincreasesrevenue,butthedeclineinpricedecreasesrevenue.Theoveralleffect dependsontheelasticityofthedemandcurve.Ifthedemandcurveisinelastic,marginalr

14、evenuewillbenegative. 4. Figure1showsthedemand,marginal-revenue,andmarginal-costcurvesforamonopolist.The intersectionofthemarginal-revenueandmarginal-costcurvesdeterminestheprofit-maximizinglevelofoutput,Qm.Thedemandcurvethenshowstheprofit-maximizingprice,Pm. 5. Thelevelofoutputthatmaximizest

15、otalsurplusinFigure1iswherethedemandcurveintersectsthemarginal-costcurve,Qc.Thedeadweightlossfrommonopolyisthetriangularareabetween QcandQmthatisabovethemarginal-costcurveandbelowthedemandcurve.Itrepresents deadweightloss,sincesocietylosestotalsurplusbecauseofmonopoly,equaltothevalueofthegood(meas

16、uredbytheheightofthedemandcurve)lessthecostofproduction(givenbytheheightofthemarginal-costcurve),forthequantitiesbetweenQmandQc. 6. Thegovernmenthasthepowertoregulatemergersbetweenfirmsbecauseofantitrustlaws.Firmsmightwanttomergetoincreaseoperatingefficiencyandreducecosts,somethingthatis goodforso

17、ciety,ortogainmonopolypower,whichisbadforsociety. 7. Whenregulatorstellanaturalmonopolythatitmustsetpriceequaltomarginalcost,twoproblemsarise.Thefirstisthat,becauseanaturalmonopolyhasaconstantmarginalcostthatislessthanaveragecost,settingpriceequaltomarginalcostmeansthatthepriceislessthanaveragecost

18、,sothefirmwilllosemoney.Thefirmwouldthenexittheindustryunlessthegovernmentsubsidizedit.However,gettingrevenueforsuchasubsidywouldcausethegovernmenttoraiseothertaxes,increasingthedeadweightloss.Thesecondproblemofusingcoststosetpriceisthatitgivesthemonopolynoincentivetoreducecosts. 8. Oneexampleofpri

19、cediscriminationisinpublishingbooks.Publisherschargeamuchhigherprice forhardbackbooksthanforpaperbackbooksfarhigherthanthedifferenceinproductioncosts.Publishersdothisbecausedie-hardfanswillpaymoreforahardbackbookwhenthebookisfirstreleased.Thosewhodon'tvaluethebookashighlywillwaitforthepaperbackvers

20、iontocomeout.Thepublishermakesgreaterprofitthiswaythanifitchargedjustoneprice. Asecondexampleisthepricingofmovietickets.Theatersgivediscountstochildrenandsenior citizensbecausetheyhavealowerwillingnesstopayforaticket.Chargingdifferentpriceshelps thetheaterincreaseitsprofitabovewhatitwouldbeifitch

21、argedjustoneprice. ProblemsandApplications 1. Thefollowingtableshowsrevenue,costs,andprofits,wherequantitiesareinthousands,andtotalrevenue,totalcost,andprofitareinmillionsofdollars: Price Quantity(1,000s) Total Revenue Marginal Revenue Total Cost Profit $100 0 $0 $2 $-2 90 100 9

22、 $9 3 6 80 200 16 7 4 12 70 300 21 5 5 16 60 400 24 3 6 18 50 500 25 1 7 18 40 600 24 -1 8 16 30 700 21 -3 9 12 20 800 16 -5 10 6 10 900 9 -7 11 -2 0 1,000 0 -9 12 -12 a. Aprofit-maximizingpublisherwouldchooseaquantityof400,000atapriceof$60

23、oraquantityof500,000atapriceof$50;bothcombinationswouldleadtoprofitsof$18million. b. Marginalrevenueisalwayslessthanprice.Pricefallswhenquantityrisesbecausethedemandcurveslopesdownward,butmarginalrevenuefallsevenmorethanpricebecausethefirmlosesrevenueonalltheunitsofthegoodsoldwhenitlowerstheprice.

24、 c. Figure2showsthemarginal-revenue,marginal-cost,anddemandcurves.The marginal-revenueandmarginal-costcurvescrossbetweenquantitiesof400,000and500,000.Thissignifiesthatthefirmmaximizesprofitsinthatregion. 4C0 500 1.000 Quantity Figure2 d. Theareaofdeadweightlossismarked"DWL'Deaewgigretlossme

25、ansthat thetotalsurplusintheeconomyislessthanitwouldbeifthemarketwerecompetitive,sincethemonopolistproduceslessthanthesociallyefficientlevelofoutput. e. Iftheauthorwerepaid$3millioninsteadof$2million,thepublisherwouldnprice,sincetherewouldbenochangeinmarginalcostormarginalrevenue.Theonly thingtha

26、twouldbeaffectedwouldbethefirm'sprofit,whichwouldfall. f. Tomaximizeeconomicefficiency,thepublisherwouldsetthepriceat$10perbook,sincethat'sthemarginalcostofthebook.Atthatprice,thepublisherwouldhavenegativeprofitsequaltotheamountpaidtotheauthor. Figure 3 (DnLISASH。5 0U6。一」d Quantity 2. Figure3

27、川ustratesanaturalmonopolistsettingprice,Patc,equaltoaveragetotalcost.The equilibriumquantityisQatc.MarginalcostpricingwouldyieldthepricePmcandquantityQmc. ForquantitiesbetweenQatcandQmc,thebenefittoconsumers(measuredbythedemandcurve) exceedsthecostofproduction(measuredbythemarginalcostcurve).This

28、meansthatthe deadweightlossfromsettingpriceequaltoaveragetotalcostisthetriangularareashowninthefigure. 3. Maildeliveryhasanalways-decliningaverage-total-costcurve,sincetherearelargefixedcostsforequipment.Themarginalcostofdeliveringaletterisverysmall.However,thecostsarehigher inisolatedruralareast

29、hantheyareindenselypopulatedurbanareas,sincetransportationcostsdiffer.Overtime,increasedautomationhasreducedmarginalcostandincreasedfixedcosts,sotheaverage-total-costcurvehasbecomesteeperatsmallquantitiesandflatterathighquantities. 4. Ifthepriceoftapwaterrises,thedemandforbottledwaterincreases.This

30、isshowninFigure4 asashifttotherightinthedemandcurvefromDitoD2.Thecorrespondingmarginal-revenuecurvesareMR1andMR2.Theprofit-maximizinglevelofoutputiswheremarginalcostequalsmarginalrevenue.Priortotheincreaseinthepriceoftapwater,theprofit-maximizinglevelofoutputisQi;afterthepriceincrease,itrisestoQ2.T

31、heprofit-maximizingpriceisshownonthedemandcurve:itisP1beforethepriceoftapwaterrises,anditrisestoP2after.AveragecostisAC1beforethepriceoftapwaterrisesandA。after.Profitincreasesfrom(Pi-AC1)xQto(P2- AC2)xQ2. P2P15C 4 A BnuBAaH ds 口o? Marginal Cost Average Cos1 QuantityofBottledWater Figure4

32、5. a.Figure5川ustratesthemarketforgrocerieswhentherearemanycompetingsupermarketswithconstantmarginalcost.OutputisQc,priceisPc,consumersurplusisareaA,producersurplusiszero,andtotalsurplusisareaA. PC omJoAvHOSQodo一」d Figure 5 b.Ifthesupermarketsmerge,Figure6川ustratesthenewsituation.Quantitydecline

33、sfrom QctoQmandpricerisestoPm.AreaAinFigure5isequaltoareaB+C+D+E+Fin Figure6.ConsumersurplusisnowareaB+C,producersurplusisareaD+E,andtotalsurplusisareaB+C+D+E.ConsumerstransfertheamountofareaD+EtoproducersandthedeadweightlossisareaF. PMPC asnuwAwa:05。。

34、howstotalrevenueandmarginalrevenueforeachpriceandquantitysold: Price Quantity Total Revenue Marginal Revenue Total Cost Profit 24 10,000 $240,000 $50,000 $190,000 22 20,000 440,000 $20 100,000 340,000 20 30,000 600,000 16 150,000 450,000 18 40,000 720,000 12 200,000

35、 520,000 16 50,000 800,000 8 250,000 550,000 14 60,000 840,000 4 300,000 540,000 At that point, profit is b. Profitsaremaximizedatapriceof$16andquantityof50,000. $550,000. c. AsJohnny'sagent,youshouldrecommendthathedemand$550,000fromthem,soheinsteadoftherecordcompanyreceivesallofth

36、eprofit. 7. IBM'smonopolypowerwillbeconstrainedtotheextentthatpeoplecansubstituteothercomputersformainframes.SothegovernmentmighthavelookedatthedemandcurvefacingIBM,orthedivergencebetweenIBM'spriceandmarginalcost,togetsomeideaofhowseverethemonopolyproblemwas. 8. a.Thetablebelowshowstotalrevenueand

37、marginalrevenueforthebridge.Theprofit-maximizingpricewouldbewhererevenueismaximized,whichwilloccurwheremarginalrevenueequalszero,sincemarginalcostequalszero.Thisoccursatapriceof $4andquantityof400.Theefficientlevelofoutputis800,sincethat'swhereprice equalsmarginalcostequalszero.Theprofit-maximizi

38、ngquantityislowerthantheefficientquantitybecausethefirmisamonopolist. Price Quantity TotalRevenue MarginalRevenue $8 0 $0 —— 7 i00 700 $7 6 200 i,200 5 5 300 i,500 3 4 400 i,600 i 3 500 i,500 -i 2 600 i,200 -3 i 700 700 -5 0 800 0 -7 b. Thecompanyshouldnotb

39、uildthebridgebecauseitsprofitsarenegative.Themost revenueitcanearnis$1,600,000andthecostis$2,000,000,soitwouldlose$400,000. \00 8 X o 82CM a X N ^12 3 A -- Demand 800 QuantityofCrossings Figure7 c. Ifthegovernmentweretobuildthebridge,itshouldsetpriceequaltomarginalcosttobeefficient.Butmarg

40、inalcostiszero,sothegovernmentshouldnotchargepeopletousethebridge. d. Yes,thegovernmentshouldbuildthebridge,becauseitwouldincreasesociety'stotalsurplus.AsshowninFigure7,totalsurplushasarea1/2x8x800,000=$3,200,000,whichexceedsthecostofbuildingthebridge. 9.a.Figure8川ustratesthedrugcompany'ssituation

41、.TheywillproducequantityQiatpricePi.Profitsareequalto(Pi-ACi)xQi. alnusAva:Ns。。.vQMd QuantityofDrugBottles b. Figure8 Thetaxonthedrugincreasesbothmarginalcostandaveragecostbytheamountofthetax.Asaresult,asshowninFigure9,quantityisreducedtoQ2,pricerisestoP2,and averagecostplustaxrisestoAC2.

42、c. d. 10. Figure 9 The tax definitely reduces profits. After all, the firm could have produced quantity Q2 at price P2 before the tax was imposed, but it chose not to because this level did not maximize profit before the tax occurred. A tax of $10,000 regardless of how many bottles of the drug

43、 are produced would result in the quantity produced at Qi and the price at Pi in Figure 8 because such a tax does not affect marginal cost or marginal revenue. It does, however, raise average cost; in fact, profits decline by exactly $10,000. Larry wants to sell as many drinks as possible without

44、losing money, so he wants to set quantity where price (demand) equals average cost, which occurs at quantity Ql and price PL in Figure 10.  Curlywantstobringinasmuchrevenueaspossible,whichoccurswheremarginalrevenueequalszero,atquantityQcandpricePC.Moewantstomaximizeprofits,whichoccurswheremargina

45、l costequalsmarginalrevenue,atquantityQmandpricePm. pPLPC 33U3A8O:owqq心.9」d Figure 10 11. a.Long-distancephoneservicewasoriginallyanaturalmonopolybecauseinstallationofphonelinesacrossthecountrymeantthatonefirm'scostsweremuchlowerthaniftwoormorefirmsdidthesamething. b. Withcommunicationssatell

46、ites,thecostisnodifferentifonefirmsuppliesthemorifmanyfirmsdoso.Sotheindustryevolvedfromanaturalmonopolytoacompetitivemarket. c. Itisefficienttohavecompetitioninlong-distancephoneserviceandregulatedmonopoliesinlocalphoneservicebecauselocalphoneserviceremainsanaturalmonopoly(beingbasedonlandlines)wh

47、ilelong-distanceserviceisacompetitivemarket(beingbasedonsatellites). 12. a.Thepatentgivesthecompanyamonopoly,asshowninFigure11.AtaquantityofQm andpriceofPm,consumersurplusisareaA+B,producersurplusisareaC+D,andtotalsurplusisareaA+B+C+D. Figure 11 b.Ifthefirmcanperfectlypricediscriminate,itwill

48、producequantityQcandextractallthe consumersurplus.ConsumersurplusiszeroandproducersurplusisA+B+C+D+E, asistotalsurplus.DeadweightlossisreducedfromareaEtozero.Thereisatransferof surplusfromconsumerstoproducersofareaA+B. 13. Amonopolistalwaysproducesaquantityatwhichthedemandcurveiselastic.Ifthefir

49、m producedaquantityforwhichthedemandcurvewereinelastic,thenifthefirmraiseditsprice,quantitywouldfallbyasmallerpercentagethantheriseinprice,sorevenuewouldincrease.Sincecostswoulddecreaseatalowerquantity,thefirmwouldhavehigherrevenueandlowercosts,soprofitwouldbehigher.Thusthefirmshouldkeepraisingitsp

50、riceuntilprofitsaremaximized,whichmusthappenonanelasticportionofthedemandcurve. Anotherwaytoseethisistonotethatonaninelasticportionofthedemandcurve,marginalrevenueisnegative.Increasingquantityrequiresagreaterpercentagereductioninprice,sorevenuedeclines.Sinceafirmmaximizesprofitwheremarginalcostequa

51、lsmarginalrevenue,andmarginalcostisnevernegative,theprofit-maximizingquantitycanneveroccurwheremarginalrevenueisnegative,socanneverbeonaninelasticportionofthedemandcurve. 14. ThoughBritneySpearshasamonopolyonherownsinging,therearemanyothersingersinthemarket.IfSpearsweretoraiseherpricetoomuch,people

52、wouldsubstitutetoothersingers.So thereisnoneedforthegovernmenttoregulatethepriceofherconcerts. 15. Becausethemarginalcostofthemusicwasvirtuallyzero,Napsterenhancedeconomicefficiencybecausethoseindividualswhovaluedthemusicmorethanzerobutlessthanthesellingpricewereabletoconsumeit.However,inthelongru

53、n,musiciansandrecordcompanieswouldhavenoincentivetoreleasenewmusicbecauseeveryonecouldownacopyofitwithoutpayingforit.The courtseventuallyshutNapsterdownbecausetheybelievedthatthisaccessviolatedcopyrightlaws. 16. a.Figure12showsthecost,demand,andmarginal-revenuecurvesforthemonopolist. Withoutprice

54、discrimination,themonopolistwouldchargepricePmandproducequantity Qm. QuantityofChips Figure15-12 b. Themonopolist'sprofitconsistsofthetwoareaslabeledX,consumersurplusisthetwoareaslabeledY,andthedeadweightlossisthearealabeledZ. c. Ifthemonopolistcanperfectlypricediscriminate,itproducesquantit

55、yQc,andhasprofit equaltoX+Y+Z. d. Themonopolist'sprofitincreasesfromXtoX+Y+Z,anincreaseintheamountY+Z. ThechangeintotalsurplusisareaZ.Theriseinmonopolist'sprofitisgreaterthanthechangeintotalsurplus,sincemonopolist'sprofitincreasesbothbytheamountofdeadweightloss(Z)andbythetransferfromconsumerstoth

56、emonopolist(Y). e. AmonopolistwouldpaythefixedcostthatallowsittodiscriminateaslongasY+Z(theincreaseinprofits)exceedsC(thefixedcost). f. AbenevolentsocialplannerwhocaredaboutmaximizingtotalsurpluswouldwantthemonopolisttopricediscriminateonlyifZ(thedeadweightlossfrommonopoly)exceededC(thefixedcost)sincetotalsurplusrisesbyZ-C. g. Themonopolisthasagreaterincentivetopricediscriminate(itwilldosoifY+Z>C)thanthesocialplannerwouldallow(shewouldallowitonlyifZ>C).ThusifZ C,themonopolistwillpricediscriminateeventhoughitisnotinsociety'sbestinterest.