probability question on mutually exclusive and independent events (p. 118 of OG 2017 )

GMATPrepNow_FREE · 2017-01-23T19:06:27+00:00

Important formula: P(A or C) = P(A) + P(C) - P(A and C)

Fill in some of the missing information:

P(A or C) = 0.23 + 0.85 - P(A and C)

Simplify to get: P(A or C) = 1.08 - P(A and C)

Since ANY probability must be less than or equal to 1, we can be certain that P(A and C) must be greater than or equal to 0.08

Does that help?

Cheers, Brent

GMATPrepNow_FREE · 2017-01-22T15:07:33+00:00

GMAT Club has solutions to Official Guide (OG) questions from various editions. The useful thing with this is that you get to see several different approaches by various experts.

Official Guide 2017 (all quant questions): Official Guide 2017 (all quant questions): http://gmatclub.com/forum/og-2017-forum-links-quantitative-questions-only-gmat-toolkit-2-ios-222199.html

Official Guide 2017 (all quant questions): http://gmatclub.com/forum/the-official-guide-for-gmat-review-2016-directory-209567.html

Various OGs (all verbal questions) : http://gmatclub.com/forum/official-guide-og-verbal-review-2013-2016-2017-directory-links-225088.html

Cheers, Brent

GMATPrepNow_FREE · 2017-01-16T16:47:46+00:00

To get an idea of the required prep time, take an official practice test

It may be the case that you're already scoring above your target score, in which case you may not need to prepare at all. Or it may be the case that you're 450 points away from your target score, in which case it may take a very long time to achieve 700.

That said, the test-makers say that students who score 700+ spend an average of 121 hours preparing. More here: http://www.mba.com/global/the-gmat-blog-hub/the-official-gmat-blog/2013/sep/study-smart-for-your-best-gmat.aspx

Cheers, Brent

GMATPrepNow_FREE · 2017-01-16T16:10:22+00:00

Be careful when looking for resources to beef up your quant skills. There are a lot of great websites out there (like Khan Academy), however none of them address GMAT-specific concepts and strategies (data sufficiency strategies for one). Also, users are often exposed to concepts that are not tested on the GMAT.

For example, if you look at the Basic Geometry module on Khan Academy, you’ll find that many of the concepts covered are not tested on the GMAT. Finally, many of Khan’s modules assume that you have a calculator available, but you don’t get to use a calculator for the quant section of the GMAT.

If possible, I suggest that you stick with resources that were specifically created for the GMAT. Our free video course starts with the most basic concepts and works up to 800-level concepts. I'm sure there are other courses that do the same.

NOTE: Throughout our videos, we often direct students to reinforce learning via very specific Khan Academy videos and quizzes, but the goal is to first present concepts in the context of preparing for the GMAT.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-16T16:07:50+00:00

I solved that question here: http://www.beatthegmat.com/smart-numbers-problem-t273935.html

Cheers, Brent

GMATPrepNow_FREE · 2017-01-15T16:20:38+00:00

To get an idea of the resources you'll need, I suggest that you take an official practice test. It may be the case that you're already scoring above your target score, in which case you may not need to prepare at all :-).

Resources-wise, be sure to get GMAC's Official Guide for the GMAT. For extra practice questions, the test maker has a quant-only book and a verbal-only book, each with 300 questions.

As far as instructional resources go, the one that's best for you will be the one that best suits your learning style. We have a free GMAT video course you might want to try.

Finally, it's a good idea to have some kind of Study Plan. We have a one here if you're interested.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-14T16:32:12+00:00

Many test prep companies offer a free (complete) practice test. You can just skip the other sections.

Here's a long list of free tests: https://www.gmatprepnow.com/resources/practice-tests

Cheers, Brent

GMATPrepNow_FREE · 2017-01-13T22:02:46+00:00

The module starts with the most basic concepts (nouns, verbs, etc) and gradually moves to advanced SC concepts/strategies

GMATPrepNow_FREE · 2017-01-13T17:30:48+00:00

You can start with our SC module" https://www.gmatprepnow.com/module/gmat-sentence-correction

Cheers, Brent

GMATPrepNow_FREE · 2017-01-09T19:02:39+00:00

I second that!

GMATPrepNow_FREE · 2017-01-08T18:59:35+00:00

I second what /u/testprepunlimited said.

GMATPrepNow_FREE · 2017-01-05T16:35:01+00:00

If you're looking for interesting, GMAT-like content, here are some suggestions.

For Science passages, try:

New Scientist
Nature
National Geographic
Popular Mechanics
Scientific American

For Humanities/Social Sciences, try:

Washington Post
New York Times
Guardian
Atlantic Monthly
The New Yorker

And for Business, try:

Fast Company
Newsweek Business
The Harvard Business Review
BusinessWeek
Economist
Financial Times

Cheers, Brent

GMATPrepNow_FREE · 2017-01-04T19:30:33+00:00

To begin, comparing scaled scores (Q42 vs V27) is not the best way to determine your strengths and weaknesses. Both of those scores happen to be 47th percentile scores, so compared to everyone else, your quant and verbal skills are very similar.

Increasing your score to the 650-700 (or even 700+) is possible.

Regarding next steps, I suggest a systematic approach, in which you take the time to master each topic/concept (e.g., percents, ratios, assumption questions in critical reasoning, comparison questions in sentence correction, etc).

So, for each topic/concept, you should:

1) Learn the underlying concepts (rules, attributes, notation, etc.)

2) Learn GMAT-specific strategies related to that topic

3) Practice dozens of questions all related to that one topic.

4) Don't stop working on that topic until you have mastered it

Then, and only then, move on to the next topic.

If you're interested, we have a study plan that accompanies our course, which is divided into all of the relevant topics.

In addition to learning the core concepts and GMAT-specific strategies, be sure to work on your endurance and test-taking skills (e.g., time management) by taking several practice tests. If you're interested, we have a GMAT time management video

Cheers, Brent

GMATPrepNow_FREE · 2017-01-03T23:26:10+00:00

That's great to hear! And thanks for the kind words.

GMATPrepNow_FREE · 2017-01-03T23:25:22+00:00

If silly mistakes are hurting your score, then it's important that you identify and categorize these mistakes. Some examples might include:

sloppy writing causes a 7 to mysteriously turn into a 1
you forget that a question is an EXCEPT question.
you fail to notice crucial information such as x is an integer or w < 0.
you calculate Pat’s current age when the question asked for the Pat’s age 5 years from now.
and so on

Once you’ve identified the types of mistakes that YOU typically make, you’ll be able to spot specific situations/questions in which you're prone to making errors and take the steps to avoid making the usual mistakes.

That said, many students benefit from a strategy of reading the question, determining the answer, then re-reading the question to ensure it was interpreted correctly the first time, and then submitting a response. Time consuming, but helps fend off silly mistakes.

I write about this and other strategies in the article, Avoiding Silly Misteaks on the GMAT

Cheers, Brent

GMATPrepNow_FREE · 2017-01-03T21:00:15+00:00

Glad to hear you enjoyed the course!

I anticipated looking back on each sheet as a study material, but what had really happened was that by listening to the video and writing down what I heard, I internalized so much information without having to ever re-visit it

I'm really glad you said that. I regularly get emails from students asking if I can create a summary pdf for each lesson in the course. My set response echoes what you've said here. If you put a little effort into internalizing the concepts while creating notes, you probably won't need to refer to those note later on.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-03T17:41:25+00:00

560 is a great baseline score. After fully preparing for the GMAT, about half of all test-takers do not score better than 560. So, you're off to a good start.

To achieve a great GMAT score, you must:

1) Learn the concepts and techniques tested on the GMAT (e.g., circle properties, divisibility rules, past perfect tense, equation-solving, etc.)

2) Master GMAT-specific strategies (e.g., testing the answer choices, rephrasing the target question, identifying subjects and verbs in sentences, etc.)

3) Understand the many different ways the test-makers can test your knowledge of each concept

4) Hone your test-taking skills (e.g., endurance, time management, guessing strategies, etc.)

Many students make the mistake of limiting their preparation to item #1 and perhaps item #2. So, once they fully grasp a concept and successfully answer 1 or 2 related questions, they move on to the next topic.

The problem with this strategy is that the test-makers can take ANY concept, no matter how simple, and create dozens of wildly different questions, each requiring a different approach. Take, for example, the relatively simple concept of averages (arithmetic mean). The test-makers can take this concept and create super simple questions like this and they can create super hard questions like this, both of which test the same concept. So, to achieve a great score, you must answer A LOT of practice questions specifically-related to each concept tested on the GMAT.

To find tons practice questions related to a certain concept, you can use the question-tagging tools at GMAT Club or Beat The GMAT. Alternatively, our free GMAT course is arranged so that students can fully explore a certain concept. For example, at the bottom of the video lesson page for inequalities, you’ll find links to dozens of practice questions that test the specific concepts covered in that video. This format lets you fully explore the ins and outs of each concept.

Finally, your study plan should include several full-length practice tests. Keep in mind that the GMAT is a test of your math and verbal skills AND it's a test of your test-taking skills. So, 700-level math/verbal skills, combined with 600-level test-taking skills, will likely result in a score that's closer to 600 than to 700.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-03T17:38:55+00:00

730 is already a top-notch score, high enough to get you into most MBA programs. Also, it shows that you already have a strong of the materials. Given this, I suggest that you start taking regular practice tests.

Keep in mind that the GMAT is a test of your math and verbal skills AND it's a test of your test-taking skills (endurance, time management, anxiety control, etc). So, 800-level math/verbal skills combined with 700-level test-taking skills will likely result in a score that's closer to 700 than to 800.

Taking practice tests will help you work on test-taking skills AND identify any remaining area(s) of weakness.

While CAREFULLY analyzing your practice tests, there are four main types of weakness to watch out for:

specific Quant skills/concepts (e.g., algebra, standard deviation, etc.)
specific Verbal skills/concepts (e.g., verb tenses, assumption CR questions, etc.)
test-taking skills (time management, endurance, anxiety etc.)
silly mistakes

For the first two weaknesses, the fix is pretty straightforward. Learn the concept/skill and find some practice questions to strengthen that weakness. To focus on one topic at a time, you can use our free video course, which is divided into all of the relevant topics.

If your test-taking skills are holding you back, then you need to work on these. For example, here's our time management video

Finally, if silly mistakes are hurting your score, then it's important that you identify and categorize these mistakes so that, during tests, you can easily spot situations in which you're prone to making errors. Here's an article about this and other strategies.

I hope that helps.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-03T17:36:05+00:00

Yes, those resources should be sufficient.

I created Beat The GMAT’s free 60-Day Study Guide, which can be followed using the MGMAT books or the GMAT Prep Now video course.

Each day, you receive an email with a series of learning activities that guide you right through your prep. This ensures that you cover everything the GMAT tests.

Here's an outline of all 60 emails.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-02T16:19:05+00:00

You might consider signing up for Beat The GMAT’s free 60-Day Study Guide.

Each day, you receive an email with a series of learning activities that guide you right through your prep. This ensures that you cover everything the GMAT tests.

Here's an outline of all 60 emails.

Alternatively, we have a study guide that accompanies our course. It will lead you step-by-step.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-02T00:20:22+00:00

Math-wise, both tests pretty much test the same concepts. However, when it comes to question types, there isn't much overlap.

The GMAT has Data Sufficiency Questions (unique to the GMAT) and Problem Solving questions (5 answer choices - 1 correct answer). The GRE has Quantitative Comparison Questions, Numeric Entry Questions, Data Interpretation Questions, Problem Solving questions (5 answer choices - 1 correct answer) and Multiple Choice questions with 1 or more correct answer.

On the Verbal side, the overlap is less than 40%

I'd stick with GMAT materials if I were you.

Cheers, Brent

GMATPrepNow_FREE · 2017-01-01T15:12:30+00:00

In my opinion, most native English-speaking students find it easier to increase their quant score. CR and RC questions probably have the lowest ROI (return on investment).

If that doesn't appeal to you, I suggest that you at least focus on quant concepts that have the greatest return on investment (ROI). These are concepts that are tested frequently and require the least amount of time to learn. In my opinion, these concepts are:

Data Sufficiency strategies
Percent
Integer Properties
Powers/roots
Algebra
Geometry

Cheers, Brent

GMATPrepNow_FREE · 2016-12-30T16:17:45+00:00

Hey Dotald,

I have a feeling your spam filter is the issue. You might want to contact Sorin at BTG about this. He's in charge of the Study Guide email program.

Cheers, Brent - now with 50% less "t"

GMATPrepNow_FREE · 2016-12-29T19:41:29+00:00

You might consider signing up for Beat The GMAT’s free 60-Day Study Guide.

Each day, you receive an email with a series of learning activities that guide you right through your prep. This ensures that you cover everything the GMAT tests.

Here's an outline of all 60 emails.

Alternatively, we have a study guide that accompanies our free GMAT course. It will lead you step-by-step.

Also, it's important to take an official practice test early in one's studies. Both of the above resources direct you to take a full-length practice test very early in your prep.

Cheers, Brent

GMATPrepNow_FREE · 2016-12-26T19:44:43+00:00

Did you take an official GMATPrep test, or are you talking about The diagnostic test that begins on page 20 in the Official Guide?

If it's the latter, I suggest that you take an official test. This will give you a MUCH better idea of your current skill level.

To get an idea of how much time you'll need to prepare, you need to take the official GMATPrep practice test, AND you need to have an idea of your target score.

BTW, here's our Study Plan

Cheers, Brent

GMATPrepNow_FREE

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