正确答案：(a)ThebreakevensalesrevenueforSwimCois$90,000.Thecompany’sprofit,tothenearest$10,000,if500athletesattendthecourseis$20,000($140,000–$120,000).(Fromthegraph,itisclearthatthepreciseamountwillbenearer$17,000,i.e.$140,000–approximately$123,000.)(b)CoststructureFromthechart,itisclearthatLineCrepresentsfixedcosts,LineBrepresentstotalcostsandLineArepresentstotalrevenue.LineCshowsthatinitially,fixedcostsare$20,000evenifnoathletesattendthecourse.Thisleveloffixedcostsremainsthesameif100athletesattendbutoncethenumberofattendeesincreasesabovethislevel,fixedcostsincreaseto$40,000.LineBrepresentstotalcosts.If100athletesattend,totalcostsare$40,000($400perathlete).Since$20,000ofthisrelatestofixedcosts,thevariablecostperathletemustbe$200.Whenfixedcostsstepupbeyondthispointatthelevelof200athletes,totalcostsobviouslyincreaseaswellandLineBconsequentlygetsmuchsteeper.However,sincetherearenow200athletestoabsorbthefixedcosts,thecostperathleteremainsthesameat$400perathlete($80,000/200),eventhoughfixedcostshavedoubled.If300athletesattendthecourse,totalcostperathletebecomes$300each($90,000/300).Sincefixedcostsaccountfor$40,000ofthistotalcost,variablecoststotal$50,000,i.e.$166·67perathlete.So,economiesofscaleariseatthislevel,asdemonstratedbythefactthatLineBbecomesflatter.At400athletes,thegradientofthetotalcostslineisunchangedfrom300athleteswhichindicatesthatthevariablecostshaveremainedthesame.Thereisnofurtherchangeat500athletes;fixedandvariablecostsremainsteady.RevenuestructureAsregardstherevenuestructure,itcanbeseenfromLineAthatfor100–400athletesthepriceremainsthesameat$300perathlete.However,if500athletesattend,thepricehasbeenreducedasthetotalrevenuelinebecomesflatter.$140,000/500meansthatthepricehasgonedownto$280perathlete.Thiswasobviouslynecessarytoincreasethenumberofattendeesandatthispoint,profitismaximised.1