Download - Pagalguy CAT 2009 DI.pdf
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Publishedonwww.PaGaLGuY.com|August17,2009
NewQuantDI,NewStrategy
ByTCYonline.com
There is no need to panic, guys;
CAT 2009 is no different from any past CAT as regards Quant & DI.
AsaseriousCAT09aspirant,doyoucompletelyagreetoit?
Although there is no need to panic, CAT 2009 is certainly different from the past CAT as regards the right ways to
approachit.WehavebeenassuredmanytimesthroughofficialnotificationsaboutCAT2009thatIIMsaretryingtokeep
the test as close to theoldpaperpencilbasedpattern as possible. The freedomoffered in a LinearComputerBased
formatsupportstheirclaim.However,thefactthatitwillbeheldonacomputerscreenisstrongenoughtomakeusre
visitourtesttakingstrategies.Theneedtoreduceorcounterbalancethetimewastageperquestion,whichseemsto
beacertainoutcomeof reading thedata from computer screen,cannotbeoveremphasized.This, togetherwith the
fact that CATQuant&DI are gettingmore reasoningoriented,would proveour excessive dependenceon thequick
calculationfacultiesamere illusion.Thismirage, ifnotdealtwithcarefullytoday,willanyhowdisappear inNovember
end.Nevertheless,todaysmistakeswouldbetomorrowsblunders.
THELOGICPREVAILS
PastfewyearshaveproventoeachseriousMBAaspirantthata99.99PercentileinCATisbeyondquickcalculationsand
VedicMath.Thoughtheseskillsareessentialtosetthemood,theyhardlyhavehelpedaCATtakerwhodoesnotknow
howtologicallyapproachaQuantorDIproblem.Probably,thatsthereasonwhytestmakersareturningtowardsmore
logicalproblemsandlesscalculationthirstysitters.YourMOCKOnlineCATscoresstandwitnesstothehardfactthatas
the Quant and DI problems turn more logical the time per question is bound to increase. This is because a logical
problemneedsalogicalsolutionandtobreakthecodeyoumustspendtimeanalyzingthegivendata.Hence,thereisa
needtocurbthistimeflubeforeitcausesmajordamage.
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AHOLISTICAPPROACH
Ifweanalyticallyassessthechallengesacomputercanpose,wecanreachthesocalledHolygrailstrategyforCAT09
QuantandDI.TheanalysisbyTCYonlineexpertsbroadlyexposes5majorchallengesaCAT09QuantorDIproblemcan
pose.Theyare:
1. Concentration Challengewhich is the root cause of having to RERERERead a question statement /
answerchoices/achart/anequationinordertounlocktherelevantinformationinit.
2. OpticalIllusionChallengewhichleadsustoassumetheNototherwisegivenstherebydeviatingfromthe
logicandfallingintothesettrap.
3. ChallengeofRelevancewhich,ifignored,maypushusintothedatawarehouseofthechartorgraph.
4. Challenge of Consistencywhich although a byproduct of poor concentration on computer screen, can
challengeourcapabilitytostayconsistentwithasingleunitofthedataespeciallytheoneusedintheanswer
choices.
5. Challenge of Interpretation which is caused by many statements which are difficult to retain in mind
(becauseyoucannothighlightanyofthem).
And there is only oneway tomeet these challenges Commonsense.However, it canbe easily translated into
specificsasfollows:
NO. CHALLENGE EXAMPLES
1 Concentration Thinkofaquestionbasedonlogicalarrangement.Youreadthequestionanddraw
aframeworkontheroughpaper;movetoanswerChoice1doesntfit;Choice
2 seems closer; Choice 3 is weird; Choice 4 can also be the answer and
Choice5canneverbetheanswer.Allchoicesscanned.Now,youdecidetolook
attheframework(fromyournotes)again.Nowbythetimeyoucomebacktothe
choices, youhave forgottenwhichwerecloserandwhich couldbeskippednow.
Actually,nowyoumusthavelookedat2ndand4thonlyandsavedalotoftimebut
youcouldnotstrikeoff1st,3rd&5thastheyareonthecomputerscreen.Thenhow
shouldyousavetime?
Simplybywritingtheimportantonesonthescratchpaper.E.g.
24inthiscase.
So,themomentyoucomeback,youdconsideronly2nd&4th.
Sometimes the question statements are either very lengthy or involve a lot of
ambiguousdatawhichotherwisecanbesimplifiedonthescratchpapersimplyby
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formulatingtheprobleminstepsasyoureadit.
ThishasbeenexplainedinanexamplefromCAT2007below.
2 OpticalIllusion Remember that diagrams in the questions are NEVER drawn to scale (unless
specified otherwise). Hence, a triangle may look exactly like a Right Angled
Triangleanditwouldnotbeclearlymentionedinthequestionstatement.Youmay
very easily fall into the trap if you do not redraw it as a scalene / isosceles
(whateverthegivendatasuggests)onyourscratchpaper.Suchkindofillusionsare
verycommoninGRE,anothertestadministeredbPrometric.
Weknowthatthefigures intheGeometryproblemshaveangles.Sometimes,we
justestimate theanswerbasedonanangle that looksbigger (or smaller)asper
thefigure.Manytimes,smalleranglesaredeliberatelyshownbiggerinsizemaking
usfellintothetrap.
Anexamplebelow(frompastCATs)explainsopticalillusion.
3 Relevance Many a time, it has been seen that a graph or a chart in DI contain a lot of
informationorsometimesstudentwillhavetorefertwochartstoanswerasetof
questions.Here,whatwegenerallydoisthatwestartunderstandingthecomplete
stuff and the relation of all the parameters with respect to one another E.g.
ProductionofRice,Wheat,PulsesinMaharashtra,Punjab,U.P,MPetc..Wetryto
understandeverypiecewhereasinsomequestionssomeitemsarenotcoveredor
stated. To add to the confusion, doing this on computer screen consume even
moretimebecauseoflowconcentrationproblem.Hence,approachinDIshould
be Question centric and NOT data centric especially in the Round 1 of your
attempt.
ThishasbeenexplainedinanexamplefromCAT2003below.
4 Consistency Sometimes there are 2 graphs to be referred to in one Questionset. Here we
should specifically notice units (cm,m, km) ofmeasurement in both the graphs.
Sometimes theseunitsarekeptdifferent inbothgraphs.That is, inonegraphall
distancesaregiveninmwhile inother theyaregiveninkm.Andwefell intothe
trap.
Additionally, ithasbeenseen thataconsistentformulationofaproblemon the
roughpapercanunlockallthevariablesandconstantsinordertoreachmultiple
answers. This is especially through in case of problems involving logical
arrangementofthedataorthoseinvolvingVennDiagrams.
ThishasbeenexplainedinanexamplefrompastCATsbelow.
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5 Interpretation In many DI questions involving logical arrangement of data, the proper
interpretation of the data in the form of tables and flowcharts helps a lot in
reachingthecorrectanswer.
ThishasbeenexplainedinanexamplefrompastCATsbelow
HereareafewexamplesfrompastCATs:
Concentration
Question1
Solution1:
Inatournament,therearenteamsT1,T2,...,Tn,withn>5.Eachteamconsistsofkplayers,k>3.The
followingpairsofteamshaveoneplayerincommon:
T1&T2,T2&T3,.,Tn1&TnandTn&T1
Nootherpairofteamshasanyplayerincommon.Howmanyplayersareparticipatinginthe
tournament,consideringallthenteamstogether?
(1)n(k1) (2)k(n1) (3)n(k2)
(4)k(n2) (5)(n1)(k1) (CAT2007)
Suchquestionstatementsdemandgoodconcentration.Here,thegivenpairsconfuseus.However,ifwe
startformulatingtheproblemonthescratchpaperasweread,lifegetseasier.
Forinstance,Ournotesgosomethinglikethis:
Therearenteams
kplayersineachteam
npairs(theconfusingpartwasthissimple)ofteamshave1playerincommon.
So,theanswerisnkn=n(k1).
Answer(1)
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OpticalIllusion
Question2
Solution2:
Inthefigure,AB=BC=CD=DE=EF=FG=GA.ThenDAEisapproximately:
(1)15o(2)20o (3)30o (4)25o (CAT2000)
ItisgiventhatAB=BC=CD=DE=EF=FG=GA;However,inthefigure,thesesidesdonotseemtobe
equal.Hence,inordertoaccuratelyreachthesolution,wehavetoproceedwiththegivendataandNOT
accordingtothegivenfigure.
Workfromthechoices.
IfweputA=15,thenC=15(isosceles)andthenkeepcalculatingtheanglesfurtherwecanreachthe
solutionfast(forthisyoumusthavedrawnthefigureontothescratchpaper).
Makeadjustmentsinyourassumptionsbykeepinginmindthatthesumofanglesofthebigtriangle
mustbe180o
Youwillfindthatonly25ocomesastheresult.
Answer(4)
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Relevance
Question3
Solution3
Per Capita Availability of Tea (gms) in Chaidesh
487 464510 544
566
0
100
200
300
400
500
600
1995 1996 1997 1998 1999
Year
(Note:Availabilityisdefinedasproductionlessexport.)
Production and export of Tea (Chaidesh)
660
645
587
561
421
220
215
209
189
207
0 200 400 600 800
1999
1998
1997
1996
1995
Export (million kg)
Production (million kg)
Inwhichyearduringtheperiod199699wasChaideshsexportoftea,asaproportionofteaproduced,thehighest?
(1) 1996 (2)1997 (3)1998 (4)1999 (CAT2003)
Alotofdata,isntit?
Butifyoureallyrefertothequestionfirstyouwillfindthatinordertoanswerit,wedontatallrequirethefirstchart.Justconcentrateontherequireddatatosolvethisquestion.
Fromsecondchartwecansaythatitishighestin1997.
Hence,rememberthemoreyoureadwithoutreferringtothequestion,themoreyoullgetconfused
(andthereforewastetime).
Consistency
Directions
Eighty five childrenwent to an amusement parkwhere they could ride on themerrygoround, roller
coaster,andFerriswheel.Itwasknownthat20ofthemtookallthreerides,and55ofthemtookatleast
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Question4
Question5
Solution4
&5:
twoofthethreerides.EachridecostRe1,andthetotalreceiptoftheamusementparkwasRs145.
Howmanychildrendidnottryanyoftherides?
(1)5 (2)10 (3)15 (4)20
Howmanychildrentookexactlyoneride?.
(1)5 (2)10 (3)15 (4)20
Totalchildren =85
Childrenwhohavetaken3rides =20
Childrenwhohavetaken2rides =5520=35
Childrenwhohavetaken1ride =145(203+352)=15
Childrenwhohavetaken0rides =85(20+35+15)=15.
Therefore,ifweputallthegiveninformationinaconsistentway,wecananswerboththequestions
together.
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Interpretation
Question6
Solution6
Achemicalplanthasfourtanks(A,B,CandD),eachcontaining1000litersofachemical.Thechemicalis
beingpumpedfromonetanktoanotherasfollows:
FromAtoB@20liters/minute
FromCtoA@90liters/minute
FromAtoD@10liters/minute
FromCtoD@50liters/minute
FromBtoC@100liters/minute
FromDtoB@110liters/minute
Whichtankgetsemptiedfirstandhowdoesittake(inminutes)togetemptiedafterpumpingstarts?
(1)A,16.66 (2)C,20(3)D,20 (4)D,25 (CAT2005)
Wouldyoutakethechancetowriteallthedataonthepaperagain???
Hey!Youhavegottoworksmarthere!
Justputthegiveninformationintherequiredformat.
A B C D
20 +20
+90 90
10 +10
50 +50
100 +100
+110 110
50 liters is goingaway from tankD everyminute.Hence itwillget emptied firstand in1000/50 =20
minutes.
Answer(3)
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AfewmorethingsonecanexerciseinhisMOCKsare:
Keepinmindthesameoldplanofdoingthepaperin3rounds.Nowasthetestisoncomputeryoumustfollow
a very logical approach to select the questions in Round 1 and 2. For instance, In DI youmust attempt the
questions that can be answered by read minimum information from the graphs / charts. In Quant, ones
involvingminimumequationsshouldbepreferred.Also,sometimesthereare23questionsbasedononeset
of data. They are also expected to consume less timeonce theproblem is properly drawnon to the scratch
paper. Here we are assuming that Prometric will allow you to move back and forth among the questions.
However,ifitdidnotallow(highlyunlikely)youtomoveback,yourtimeperquestionwilldefinitelyincreaseas
youwillhavetoskipaquestiononlyifyouknowyoucannotdoitatallgiventhefactthatyouwillnevercome
backtoit.
Also it is expected that as the test goes online the percentage of DataSufficiency question will increase.
Moreover, it isalsoexpected that theamountofdata in theGraphsandchartswillbe lessandwitha logical
approachesdescribedaboveyouwouldbeabletocomeupwinners!
Allthebest!!
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