GMAT Ninja Quant Ep 0: How to Approach GMAT Quant

hi everybody Charles from G ninja toring here today we're going to talk about how to best optimize your approach to Quant and data sufficiency questions on both the GMAT executive assessment I want to be totally clear about something from the start this is not a math video in the way you might conventionally think of it I'm not going to take you through algebra formulas geometry percentages anything like that instead I want to talk about something that for an Adaptive test like the GM EA is actually more important and that's how you approach the questions how

you ensure that you don't make those careless errors that can absolutely kill your score on these adaptive tests also to be clear we're going to talk about both Quant and data sufficiency if you're taking the GMAT Quant is exclusively problem solving questions data sufficiency appears on the data Insight section but they often cover some of the same domains of mathematics so we're going to talk about process for both those all at the same time if you're taking the executive assessment problem solving and data sufficiency are both on the Quant section so throughout our videos here

we're going to deal with problem solving and data sufficiency in all the Quant videos so help you out with both the qu section and also the data inside section if you are a GMAT test taker now if you tend to make careless errors even if it's a fairly small number of them this video is absolutely for you we're going to give you some processes to help you build better habits as a test taker make sure that you never beat yourself on either of these exams now if you're somebody who's been studying for quite a while

for the GM EA and you have no idea why you're struggling you think you know a whole bunch of of math and you're still struggling to get your score up this video is absolutely for you because odds are really really good that what that's happening is that you're making those careless errors that can absolutely crush your score or you're being inefficient or you're mismanaging your time in ways that if you have a really good strong approach to questions that is going to get better and if you're totally new to the GM EA this is also

a great starting point um you might have a lot more to learn in terms of the actual content of the test but if you have really really good processes from the start you never make careless errors manage your time well you're really flexible you are going to save yourself so much steady time and the path to your target score is going to be much much quicker all right plan for today I want to talk briefly about how the algorithm works on adaptive test like the GMAT and EA just so you get a sense of what's

going on underneath the hood then we're going to hop into three questions again not melting your face off with super hard math here at all um they're going to be things that are fairly foundational first question is going to probably not be anything that you're going to miss because of the math itself only if you're doing something silly with your process second question we'll do data sufficiency talk about how best to approach that third question I'll give you something that requires a little bit more flexibility and we'll talk about how to bake that into your

approach to these questions all right adaptive algorithm on these tests I'm going to massively oversimplify here but the essence of adaptive testing is the algorithm is trying to find the level of question at which you get roughly roughly roughly half right half wrong so let's suppose you're a fairly strong test taker you get the first few questions right the questions are going to keep getting harder and harder until you really start squealing same idea if you're if you're struggling a little bit questions will get easier until the questions hit a level that is uncomfortable for

you but not absolutely overwhelming upshot here is even if you're really really really good at Quant odds are good you're going to miss a whole bunch of questions and that's true of all the sections of the gmet of the EA unless you're way way up at the top of the score scale in which case I'm not sure why you're watching this video uh you are going to miss a bunch of questions and that is totally fine the key is you want to miss the hard ones only if you miss the easy ones what's going to

happen is you're never going to see those hard ones and your score is going to be stuck much lower than you want it to be so absolutely crucial on these tests that you avoid those unforced errors manage your time really well and that's what we're going to focus on here today very very quick thing uh there was an academic study done I don't know 10 15 years ago uh by a couple of my favorite psychometricians and yes I am nerdy enough to have favorite psychometricians and it wasn't specifically on GMAT data but it was using

the same kind of model a three primary logistic model if you're falling asleep I'll bring it back to reality in just a second here's the upshot of the study they basically said imagine that we have somebody who scores in the 90th percentile on a test like the GM EA now what we're going to do they're they're going to behave normally for most of the test except they're going to randomly miss the first two questions in a way that they wouldn't normally if you're scoring the 90th percentile you're probably going to get those first couple questions

right odds are so the modeling they basically did is they said okay we're going to take somebody who behaves like a 90th percentile scorer they're going to miss the first two questions after that they behave normally what happens to their score so in this simulation study on average people lost about 80 points they were the equivalent to 80 points on their score if they just made bad errors on those first two questions and otherwise behave like their normal 90th percentile cells so in the context of the GMAT that's a 90th percentile around a 645 or

655 imagine losing 80 points Landing in the the 500s so that's the kind of damage you can do to your score if you make careless SS again miss all the hard ones you want to that's not going to ruin your day don't miss the ones that are easy for you so regardless of where your math skills are maybe you're great at it maybe you're a little bit shaky regardless the biggest kid of these tests and I know it sounds ridiculous totally unsexy it is make sure you don't beat yourself okay with that if you like

our videos please hit the like button please subscribe this is part of a a full comprehens of GMAT EA course that we we give out for free online if it's helping you out um and it's helping you save money please donate to some of our favorite Charities we love giving out the stuff for free and if you need more one-on-one help please hit us up at jat ninja.com we do one-on-one tutoring as well okay with that uh here's your first question not going to be a super tough one nothing super hard on the math but

it if you're being really good about your process shouldn't be hard for you but regards to whether you get it right whether you get it wrong we're going to talk about ways to make sure that you never miss stuff like this and you have a nice systematic way of approaching it go and take a couple minutes on this one e e e e all right I promise you two things in introduction promise you the questions would not be very hard mathematically if you can do basic arithmetic you can answer this question correct from a mathematical

standpoint really Nery little sidebar here you'll notice that the section both EA and GM it's not called math it's called quantitative reasoning for a long time I just thought they were being kind of pretentious to be honest realize over time that that really is what they're trying to test you on Data Insights is trying to test you on your ability to process data in a real world kind of way Quant is trying to test your ability to reason with mathematics as kind of the language underneath it so this is more about reasoning and reading than

it is about math welcome to the GMAT welcome to the EA I also promised a totally unsexy boring thing that's going to put half you to sleep but it is so crucial that you do this every single time with complete consistency every single time I want to read the question twice before you do anything the easiest mistake to make on Quant questions is you just launch in you do the first thing that comes to mind you misread the question you misread some little modifier in this case we've got a pretty layered question we know a

lot of things about A and B they're two digigit integers two digits they're integers that's two different characteristics there we've got inequalities going in opposite directions closest to the maximum possible value you jump over one of those words that I just underlined you're probably going to miss the question read twice take a breath always always always second step I want you to plot your path forward instead of just jumping into the first thing that comes to mind typical GMAT EA question it might have six different solution paths on a on a moderately difficult question your

job when you're under time pressure is to find one of the more efficient paths if you do the first thing that comes to mind you might spend an eternity you might do something that's a dead end you might just be doing something silly take a breath a lot of this test is about building efficiency choosing the right paths forward take a moment take a breath it's going to save you time in the long run if you do this and super crucial again the test is going to keep getting harder and harder if you're doing well

you're not going to be a most of you won't be able to spend as much time as you want in every single question if you're overwhelmed if you don't know how to do the question if you read it twice you think through you play with it a little bit you don't see a path forward no shame at all and saying hey my path forward is crap I'm going to guess I'm going to flag that question and move on you can always come back to them later at the end of the test you can change up

to three answers per GMAT section change anything you want within a little miniature section on the executive assessment so be honest with yourself if you don't see a path forward after a little bit guess flag that question move on again you can always come back check every step as you go it doesn't matter who you are 4 * 7 is sometimes 32 we all make that mistake people who get perfect scores it's not because they're robots that never make mistakes it's because they catch them every time every step you take take a breath make sure

you're doing the right thing we all make dumb mistakes as we're doing little bits of arithmetic little bits of algebra the key is can you train yourself to catch it 100% of the time as you go look at that step you just wrote down from some other angle see if you can see something I might have done wrong and then at the end I know it sounds like you're wasting a lot of time here but read that question one more time and I know people like I don't have time to read it three times you

need to because again on a adaptive test you miss those easy questions you miss it because you misread you miss it because you made some miscalculation taking that extra few seconds to read one more time at the end it insulates you from a misread number one it insulates you from answering the wrong question which is something we see from our students all the time when they come in and it also gives you a chance to sanity check it and go hey is my answer in the right ballpark does it make some sense uh former student

of mine love you Tom if you're watching this uh love to use the term using your human brain meaning yeah use some intuition and just say does this make some sense if it does cool if it doesn't make any sense maybe you need to recheck something do this every single time not 91% of the time or 94% of the time 71% of the time if you do that you're going to make those careless errors that can kill your score remember under the time pressure of the actual exam you're more likely to do silly things your

key as you practice is to get this locked in 100% of the time okay that was the unsexy really boring part let's do some math if a be two digit integers such that a is greater than 60 B is less than 80 what's closest hey that word should always jump B at you it's my friend I like it makes me happy I'm probably not going to have to be super precise here to the maximum possible value of the product AB okay so two-digit integer maximum possible value of this what's the biggest I can make a

and have it still be two digits well it's 99 so you could say that a is equal to 99 obviously that's going to round up to 100 what's the biggest B can be B is less than 80 so biggest B can be is going to be 79 answer choices again they're being nice to you here they said closest I don't need to multiply all this out I can just go well this is close enough to 100 this is close enough to 80 that's it 80 time 100 8,000 that's it okay simple enough next I'm going

to give you a data sufficiency question same idea it's not a super hard question not melting your face off with any arithmetic here any algebra or fancy math just want to make sure that you're we're going to kind of go through something that a lot of people make mistakes on despite the fact it's not a super difficult question take you through a process that will help insulate you from the careless a so regardless whether you get it right or wrong find it easy or hard um bear with us and we'll kind of take you through

how to make sure that you're totally Bulletproof on data sufficiency as well goe and take a couple minutes on this next one e e e all right much like the first question I'm not trying to melt your face off with super crazy mathematics here that's not the point really not the heart of what you're going to see on data sufficiency questions whether you're taking the GMAT or the EA instead why I'm interest in this question is yep word problem looks very much like what you're going to see on the GMAT on data sufficiency more importantly

it's the kind of question where there's tons of ways to make mistakes that beat you here and it's not the mathematics itself just lots of ways that if your process isn't totally dialed in you're going to have trouble here so uh bear with me if you if you've seen a lot of our videos before you might have seen us model data sufficiency if that's the case bear with us I'm going to try to go through this pretty quickly for the veterans if you're totally new here I'm going to give you a quick overview of the

process that's going to optimize your performance here all right two really big ways you can undermine yourself on data sufficiency questions number one a lot of the time they're going to give you a whole bunch of information in the question itself and what I want you to do is obvious read it twice just like you would problem solving but really focus on what can I do with this question before I even look at these answer choices so don't jump straight into these answer choices take a moment and say how might I push the question meaning

how can I take this do whatever I can with the information that's given maybe write the question in different ways that are logically equivalent I'll model that here in just a moment so that's the first key make sure you're pushing the question on data sufficiency really the only thing that's fundamentally different to the process than it is for everything else on Quant second the biggest mistake we see where students undermine themselves throttle their scores it's when they prematurely combine these statements that temptation is often to say okay let me read all this stuff and you

can walk right into a horrible area if you do that I want you to keep them super super separate here's the best way to do that nothing magical here simple little thing popularized by by Manhattan Gat back in the day don't know if they came up with it but credit words do they certainly popularized it this isn't Magic but what I want you to do is do whatever you can with question first and again we'll go through this question in just a moment look at the first statement alone do not look at the second statement

really easy to combine those prematurely once you read one it's really hard to forget it you want to minimize the odds that you make that sloppy error of combining them when you're not ready to do that yet look at statement one completely by itself now if statement one is sufficient the answer must be either a or D so that allows you to cross out BCE so that is if this is sufficient to answer the question if it's not sufficient same idea you're just going to cross out a can't be a or in that scenario um

so if you're in the scenario where this is sufficient then that act of of Crossing something out that's your cue to wash your brains reread the question do your very very best to forget this thing and then you can look at statement two so again obviously if statement two is sufficient and statement one is sufficient your answer is D if only statement one is sufficient your answer is a in that scenario same idea if you started you read the question took a look at statement one made a decision decided it was not sufficient you can

cross out ad reread the question wash your brains do your best to forget it now look at statement two with fresh eyes can I answer it based on this if you can your answer must be B if you can't then and only then cross out B and try to put the two together so again most common mistake can't say it enough I know I'm broken record on this and a lot of this process stuff is super unsexy but if you're not new to the GMAT and you're struggling with your score and you think you're into

performing your Quant skills I I can guarantee you've made this mistake you kind of digest everything all at once spit up the answer is C when really it's a or b or d or or maybe even e so be really really careful keep these statements separate not sexy but the single most important thing you can do second most important push that question along as best you can all right let's jump into this guy so Chuck spent a total of $360 on beer cookies and diapers there's a little Glimpse inside my household um how much did

he spend on cookies last week okay uh so I've got an there that they give me right in the beginning so we spend a total of 360 on three things generally the GM's going to be really nice to you give you things that kind of create nice variables beer cookies diapers hey look BC and D very nice of them they don't always do that but a lot of the time they're gentle with that sort of thing all right so total spending on beer cookies and diapers equals 360 so B plus C not plus plus b

plus C plus d equal 360 what's my question well I want to know how much he spent on cookies the Temptation that most test takers have especially if you're new to the GMAT new to the EA just jump in there okay I'm looking for cookies um I don't want you to do that take a moment see if there's anything else you can do to push that question in this case I want to know what's going to get me C and if you think about this equation a little bit you go wait a minute if I

know B plus d that allows me to get C so I can rewrite the question as what is the value of B plus d if you don't see that right away I mean I could rewrite a couple different ways I could just kind of Slide the C over and say C + B + D equal 360 hopefully that makes it clear that b plus d is going to unlock the value of C or you could solve for C you get C = 360 minus B plus d so again anything you can do to not throw

your dry eras markers anything you can do to process the question write it in logically equivalent ways is going to help you a ton I've got two questions they mean the same thing if I can answer one I can answer the other that's going to help me see the relevance of these answer choices as I go through now again some of you might have walked in the Trap of kind of saying oh wait a minute these two answer choices if you looked at them all together right in the beginning you might have said well hey

they're kind of the same thing and so the answer must be e there all kinds of judgments you can make right off the bat take your time take a breath push that question along let's hop in here so I'm looking for either C or B plus d first statement the amount spent on beer was 3 fths of the total amount spent on cookies and diapers so B = 35ths * C + D now I really want some cookies and beer is this going to help me I don't see how it's going to so it gives

me c plus d is a function of B I've got two equations three variables that's not guaranteed that that's not sufficient in general but here there's just there's just no way there's no way to rearrange this to get what you want so it is not a d i can cross those two out and again wash my brains forget about what I just saw here what am I looking for again I'm looking for C or I'm looking for B plus d on the statement two with fresh eyes the amount spent on cookies was 3 fifths the

amount spent on beer plus diapers wait a minute this is catching my eye here so again the reason we did all that is so it's easier for us to see the relevance of these answer choices there's my B plus d now maybe I'm not certain right out of the gate if I can solve that but let me try let me try rearranging this a little bit see if it gets me some where what's B plus d so B plus d is I rearrange this equation I'm just going to multiply both sides by 5/3 so I

get rid of that 3 fths here so that's going to be 5/3 * C and now we're in business if you take this original equation maybe this version of the equation might be the easiest one to see it with if I substitute this in right here I've got what I need so C+ 5/3 C I'm going to write it up here because I'm running out of space Cas taking a different color here C + 53 C = 360 obviously I can solve it for C now that's what I was looking for so statement two is

sufficient the answer is B welcome to the GMAT ladies and gentlemen a lot of things just don't look the way you want them to look these two equations look totally equivalent because it's one variable is 3 fths of the combined of the other two variables put together but that can be really deceptive again they're not out to trick you they're not out to trap you the key here is is if you have really good process here you push the question you keep those statements nice and separate good things are going to happen to you I'm

a question here that is not hard mathematically but ends up being kind of tough because there's so many ways you can undermine yourself good process will fix that one other quick note here on data sufficiency I sometimes get the question are these ever going to be different what the answer choices are these are always going to be on your screen every time you see data sufficiency question on the GM EA don't worry about that that's always going to be there not going to change it'll become second nature you're going to stop looking at it have

to do a little bit of practice second thing that comes up quite a bit notice here I didn't bother solving for SE I don't actually care what the value is I care that I know that I can get the value here one equation one variable no exponents no roots no funny business we're going to be able to get C here I don't care what it is I just know that I can get it so I know that statement two is sufficient don't do calculations you don't need to do on data sufficiency I'm not saying avoid

calculations sometimes you have to and that's fine but stop once you know that you can get the answer and don't continue beyond that don't waste any time all right that's a little glimp into Data sufficiency uh if this is something you want more work on again we have a full video on data sufficiency we just kind of give you more reps on this process talk about in different context a little bit go check out that video in the Data Insights playlist for the GMAT all right one more question this one's going to require a little

bit more flexibility we talk about this unsexy General process here read twice plot the path forward it's the plotting the path forward think before you act some of you are going to see exactly what to do right at the gate most of you your first idea is going to be garbage so take a moment think about your options before you jump in absolutely a design feature that GMAT they're going to reward you for that just like for some reason I've never fully understood why this business of pushing the question they reward you for it on

so many data sufficiency questions it's a design feature why is it I don't know but it's very clearly there same thing on this next question lots and lots of different ways to solve it take a breath find the best one and I promise it won't be that hard go ahead and take a moment e e e hey everybody sorry to interrupt your Quant viewing experience with that weird big nose Tutor Guy chances are if you've made it this far in the video you're pretty serious about this whole gmet thing and if that's the case got

two things I want you to be aware of first of all if at any point in your admissions process you could use some help on your applications we would love to help you find the best admissions consultant for you so there's a little contact form available at GMAT ninja.com you can also find it in a link in our video description fill that thing out pretty short and we'll send you a list of our very favorite admissions Consultants at a number of different companies yes it includes our own company also several others that we've known for

years and Trust deeply we want to make sure you end up in the best hands we're not going to give your email to anybody else we're not going to do anything weird with it we're not going to try to sell you anything there's no Kickbacks no commissions we just want to give you our honest best takes on the best admissions consultants and go pick the one that fits your needs the best second thing we also have a comprehensive NBA admissions playlist here on this YouTube channel if you're just getting started with the GMAT haven't thought

about admissions yet I would recommend starting to watch some of those sooner rather than later get your head around the process start brainstorming a little bit I promise it's going to make your life much much easier down the road all right that's it if you've enjoyed these videos like subscribe you know the drill all right back to the Quant all right if you need more time on this one feel free to hit the pause button rewind pause um if you're struggling on this you're not alone fairly tough question again the math isn't hard you know

how to deal with fractions you know what roots are you know what exponents are at least the basics of those but you can spend a lot of time chasing really goofy paths on this question it's exactly what it's designed for and that's a jmat whole shtick quantitative reasoning not math they're going to give you a whole lot of different ways to solve even a mid-level question like this one and the question is can you see the best ways to do it in this case Okay read the question twice pretty straightforward of the following sums which

is greatest now let's think about our options that's what I want you to know in every single GMAT question on the Quant section on data sufficiency what can I do here well my first instinct first time I saw this question years and years ago oh hey yeah I can do fractions common denominators it'll be great wait a minute uh I got to add up 20 fractions I got to get common denominators for 20 different fractions that's a terrible idea okay can I think of something else is there another way to do it now what catches

my eye here whenever I see the phrasing which of the following is greatest or least again it's kind of like saying kind of like saying closest to something or to approximate they're they're inviting me to compare things not necessarily to calculate just like in that first question we did which of the following is closest they're kind of saying right at the gate wait a minute maybe I don't have to do the arithmetic down to the Nat's ass maybe I can just kind of estimate this and be okay same deal here what if I can start

comparing these and I can Lop off answer choices that are smaller than another one so if I take two answer choices and I say one of these is bigger than the other the one that's smaller of the two not my answer I can cross it out let's see if that works obviously these all kind of look sort of the same there's twos threes fours and fives in the denominators but different bells and whistles around them you could start almost anywhere lots of different opportunities here I'm kind of scanning through these and going wait a minute

I've got minuses I'm doing some subtraction in D I'm not doing any subtraction in the others let me see if that gets me somewhere no funny business in these let me see if I can just compare d and e so one minus a half one minus a half is a half so I can kind of cross that out now we can compare these I don't have to do any common denominators D half plus a third minus a quarter e half plus a third this part's the same this part is different this part is bigger than

this part all right my answer is not D cool one down this is great um now I'm just looking for the next easiest thing to compare trying to get my head around it I've got two three four and five in my denominators in E well here in B for example I'm squaring them so what does that do if I Square an integer like this I get a bigger number bigger number in the denominator means I'm going to have a smaller fraction overall one 1 over 2^ s is going to be smaller than 1 over2 1

3 squ going to be smaller than 1 over 3 and so on that means B must be smaller than e notice again I haven't done any calculations yet barely anything so similar ID I can look at C and go that's kind of similar to B each of these denominators in C is going to be bigger than each denominator in E that means each of these fractions must be smaller and now we're rumbling E and A okay same same integers 2 3 4 5 they're getting square rooted in a that means that those numbers in the

denominator are getting smaller which means the overall fraction is bigger so these have to be bigger so one over theare root of two has to be bigger than 1 over two one over theun of 3 must be bigger than 1 over three So my answer is not E and A is the winner welcome to the GMAT this is the kind of thinking they reward not that you're going to see a ton of of things that are this purely arithmetic but this kind of principle where they're going to give you lots of different options all sorts

of different ways you could slice and dice these answer choices so I see people try to kind of simplify a few of them maybe they they go ahead and multiply these out in BNC but I want you to take as much time as you need within reason to say wait a minute what is that going to do if I start down that road I've got a whole lot of fractions to simplify that way what's my plan here and see if you can think of anything better fight for a better way before you start doing stuff

one of the biggest keys to success on the GMAT yes key number one avoid those careless errors read twice can't say it enough don't beat yourself let the test beat you adaptive test it will get hard for you if you're executing well if you're managing your time well if you're not making careless errors the questions will get tough for you you want that to happen that's a good thing when it does you're going to have to let go of some stuff pick your battles really carefully um but the other big key here is they are

going to demand flexibility of you so if you can avoid those careless errors execute really really well the next Frontier is being flexible it's not about how much math you know it's sifting through your toolkit and saying what can I do on this problem to make it the most efficient I possibly can so as you get further down the road in studying I want you to really keep that in mind keep that step two in mind and really focus on okay I spent four minutes on this question when I was practicing as you look back

at it later think okay how could I've given myself 20 more seconds thought a little bit more flexibly and maybe found a better way how can I build that better into my processes I answer questions all right that's it that's how to approach the GMAT Quant section and data sufficiency which obviously is on the data Insight section if you enjoyed this video as always please please please hit that like button hit the Subscribe button uh you know where to find us if you want one-on-one tutoring and again if we're saving you money with this full

free course um please visit us g.com um and you can donate to some of our favorite Charities would love to pay that forward and if there's other Charities you love more than the ones we've chosen um let us know about it always love to hear about other causes that we can support all right thank you everybody for watching and we will see you next time