hey everyone this is Mike from GMAT ninja I'm here to talk to you about something we see a lot of our students doing something that seems like a great way to prep for the GMAT but that actually is really harmful to your score that something is studying official solutions to quant questions and if you focus too much on those solutions you'll miss a huge opportunity for improving your quant reasoning skills so I won't explain what I mean by that and then give you some concrete guidelines for making the most of your official guides first some
context the GMAT is not a Content test take the quant section for example fractions exponents ratios quadratics these are examples of the mathematical content that does in fact appear on the test for many of us especially in the u.s. learning that mathematical stuff often involved drilling a bunch of examples and then studying the steps to solve those problems so that we can mimic those steps later and because this approach worked so well for many of us in grade school and perhaps in college or university we've developed a deeply ingrained sense that improvement comes from studying
examples and understanding the explanations to problems that gave us trouble unfortunately on the GMAT this approach isn't very effective don't get me wrong you absolutely need to have a strong foundation rooted in certain mathematical content if you want to do well on the quant section if you don't know how to do exponents or quadratics for example you will be in big trouble but the quant section isn't simply testing how well you know that stuff that's because the GMAT is meant to be a reasoning test let me show you an example of what I really mean
by quantitative reasoning here's a GMAT style quant question I recommend pausing the video and trying this one on your own before we continue okay we need the sum of the reciprocals of the 5 consecutive even integers starting with 40 so that's 1 over 40 plus 1 over 40 2 plus 1 over 40 4 plus 1 over 40 6 plus 1 over 48 if you're thinking mechanically you might try adding these together by finding a common denominator or doing long division but you'll realize pretty quickly that it would be a nightmare to add these things together
using brute force instead let's try to reason our way out of it well each of the five numbers is greater than one over 50 so the sum is going to be greater than 5 times 1 over 50 or 5 over 50 and that reduces to 1 over 10 or 0.1 great we can already eliminate a and B now each of the numbers is also less than 1 over 40 so the sum is going to be less than 5 times 1 over 40 or 5 over 40 that reduces to 1 over 8 or 0.125 and now
we can eliminate choices D and E and we found the correct choice C without breaking much of a sweat this isn't the only way to solve the problem but when you're under time pressure you want your solution path to be as efficient as possible now you've probably noticed that the GMAT is really good at disguising content that you know in ways that you've never seen before you can memorize solutions to a hundred different types of exponent problems but those won't help you on test day when you see the hundred and first that's why jumping to
the back of the book whenever you see something unfamiliar isn't the best way to prepare the other problem with focusing on official explanations is that sometimes they're just not that useful check out this problem-solving question from the 12th edition official guide whoever wrote this lengthy explanation thought oh great I know how to do this let's start multiplying to get rid of those denominators and of course that approach will work eventually but imagine how long it's going to take you to do all of that messy arithmetic and how easy it would be to make a careless
mistake along the way the official explanation isn't wrong but it's not the most efficient way to solve this problem after watching the video come back to this one and see if you can come up with a better way if you need a hint remember that you can't divide by zero now here's a data sufficiency problem from the 20/20 official guide have you ever noticed that the explanation writers always seem to know exactly which numbers to pick the problem is that we don't the explanation proves that the answer C but it doesn't tell us the best
way to tackle this problem from scratch so what's up with these solutions well it's worth noting that the explanations aren't written by the same people who write the questions or even by the people who make the test so the same rigorous thought process that goes into question design isn't being applied to most of the explanations on top of that the official explanations often only give you one solution path which is not necessarily the most efficient solution path so studying official solutions isn't a good way to improve your reasoning skills instead use the official guide to
practice what you'll be doing on test day tackling unfamiliar problems and trying to find efficient solutions to them you want to use the official questions to figure out where you make mistakes and then improve your technique accordingly I'm going to share a couple guidelines on how to do that even though the value of the official explanations is debatable the official questions themselves are still extremely valuable once you've worked through a couple official GMAT guidebooks you're gonna have a tough time finding quality fresh material there are plenty of unofficial GMAT questions out there and those can
be useful in certain situations but GMAC spends a ton of money developing each and every GMAT question and test prep companies simply can't afford to compete in the words of Marvin Gaye ain't nothing like the real thing while working through your official guides I recommend doing about 30 practice problems at a time that will help you develop the endurance you'll need on test day when you've finished a set record a list of the questions you've got wrong but resist the urge to study those errors right away instead wait at least a couple days without looking
at the ones you missed and then retry them that'll give you some time to clear your head and come back to those questions fresh when you do make sure to read every question twice and take some time to think about how you're going to solve them before you dive in what you're really practicing is untangling the question looking for the most efficient solution path and then checking your work as you go even if you get it wrong both times you've given yourself another chance to strengthen your reasoning muscles okay so what if a question kicks
your butt twice then what well as here sa Elida GMAT ninja if a question is giving you that much trouble it's probably not worth the stress you can miss a third or more of the clock questions and still get a great score missing questions that you can handle is a much bigger problem so focus on the questions you got right the second time but not the first time retrace your steps and try to figure out where you went wrong did you dive down an inefficient solution path without thinking did you rush and make careless mistakes
if so you don't need to learn more math stuff you need to work on your technique and try to figure out how to avoid those mistakes and sometimes you will uncover content gaps if you got questions wrong the first time because you forgot your exponent rules or your special right triangles you should absolutely go back and review if you want to get the most out of your official guide keep your focus on the questions and how you're choosing to solve them of course a good GMAT tutor can help you make the most of your practice
but if you're on your own I hope I've helped you understand why it's a bad idea to cram quant solutions even if they're official this is Mike from GMAT ninja thank you for watching
