Showing posts with label math. Show all posts
Showing posts with label math. Show all posts

Wednesday, October 12, 2011

Jewish Problems

This is a special collection of problems that were given to select applicants during oral entrance exams to the math department of Moscow State University. These problems were designed to prevent Jews and other undesirables from getting a passing grade. Among problems that were used by the department to blackball unwanted candidate students, these problems are distinguished by having a simple solution that is difficult to find. Using problems with a simple solution protected the administration from extra complaints and appeals. This collection therefore has mathematical as well as historical value.

Get PDF with problems here at http://arxiv.org/pdf/1110.1556v1

# Posted via email from opportunity__cost

Friday, October 23, 2009

Typo hunter's on the road again

Typos happen.  Sometimes they don't bother you much.  Sometimes, the do.  Like in the books that have question and answer combos.

Like, you know, for the quantitative part of GMAT, for example.

Yes, I'm talking about the EZ basic math workbook.

It has a lot of typos.  What's worse, it has a lot of errors, too.  Like the one show above, which is page 113, question #20.  Twice 32 equals 64, but not 62.  Where the heck is editor?  Proofreader?  Anybody else?

It's not the only example, but I just wanted to show you that reviews like this (even if it's the only one), should not be ignored:

there are a lot of examples in the book that are completely wrong. The further you go in the book the worse it gets. Its like the author got exhausted by the end.

ex:
1) a question will ask you about blue ribbons but will calculate due to green ribbons.
2) some of the combinatorics questions have missing combinations that the question is asking about.

I can go on and on ...

The book is very easy and has bunch of errors. Work with it at your own risk.

BTW to put some weight behind my words: I have already taken GMAT and got above 700. 

Take care.

# Posted via email from opportunity__cost

Thursday, October 22, 2009

EZ Basic Math

Okay, I've got 200 more sample questions and 2 parts left from the EZ basic math workbook.

http://www.amazon.com/exec/obidos/ASIN/1605621579/iwhite-20

Listen. Get it if your math is really bad. I mean, you really suck. Or you feel like you suck. Otherwise, you don't need it. It sucks to be able to solve all samples. I'm not the brightest guy, but it's too easy even for me.

So I'm planning to take a pause with math and get back to Sentence Correction.

http://www.amazon.com/exec/obidos/ASIN/0982423861/iwhite-20

And only after it I'm going to spend more time with EZ advanced math workbook. I hope it would be way more interesting, because I found myself doing pretty well with The Quest for 700: Weekly GMAT Challenge posted every Wednesday on http://www.mbamission.com with answer following Thursday. Otherwise, screw the Amazon's reviews for EZ books, because they're wrong. Anyway I don't like the format of EZ books. I'd prefer to stay closer to GMAT format, because, well, you know... this is for GMAT. Why is it titled so, huh?

# Posted via email from opportunity__cost

Monday, October 19, 2009

My progress with EZ basic math

While I didn't spend a decent time with the book, the results so far so good. Out of almost 200 questions, I've yellow-marked 4 or 5 solutions, even scoring the 100% correct answers. Those solutions were a little bit easier way comparing to what I chose.

This is quite a nice number to see, however, I was expecting for something more challenging. It's easy to be a smart guy when you're facing very basic problems, isn't it? :) I'm starting to think that getting a basic math workbook was not so good idea. I should start from advanced one. However, I'm not going to drop out now, and I'm going to complete it.

# Posted via email from opportunity__cost

Friday, October 16, 2009

EZ Basic Math for GMAT

Well, I'm pissed of.  

First of all, this title sucks.  How do you imaging me telling a friend about this book when it has some many words inside?  Do they all make sense?  Doubt so.

I've read so many positives reviews about EZ books for GMAT.  Speaking about this specific book it was like 7 five-stars and 1 one-star.  None of the did mention that the basic book is so freakin' basic.

I've went through almost a hundred of questions so far, and none of them are challenging.  They are basic.  But I'll keep going.  Hopefully, this book will undercover some hidden gem and it will make me happier about the twenty I spent.

# Posted via email from opportunity__cost

Monday, August 17, 2009

Word Problems

Starting from page 345 I got into Strategies and Practices part of the book, with the opening Chapter 10 of Word Problems. The first few blocks didn't impress me. Some silly principles described in writing -- it's more like something that every person should understand himself, but not learn about.

The picking numbers principles is useful, however, I found it pretty inappropriate for examples shown there -- they can be easier solved with plain math (0.8 * 1.3 -- is it something that is hard to calculate?).

Kaplan's 3 step method for word problems in data sufficiency questions looks absurd to me. Totally.

The Chapter 10 is over now with nothing useful taken. (Read: don't buy this book.)

The Chapter 11 is AWA. While they articulate that you need to learn how to type quickly, I'd be much happier if they would tell me "how quickly"? I'm pretty comfortable with keyboard, but I know people who go way crazier in typing.

Page 364 says that the length of essay is not a factor. However, I remember references to the fact, that the length of essay still rather important thing.

As always, a point of using transitional phrases, like first, therefore, since and for example.

As always, examples in this book really suck. The Analysis if an Issue one starts like they are going to tell me the process of writing an essay step by step (which is good, by the way), but suddenly they just come up with something that my essay might look like with a whole essay text shown.

The book says I should avoid opening sentences with there is or there are. I should mention I'm doing this quite often. ;) I also should not refer to myself needlessly. (Is this a really weak point?)

In Chapter 12, which is about taking control of the test, the authors raise the question of importance of answering the first questions correctly ..."on the GMAT, if you can get the first 10 questions right, you can get lots of later questions wrong and still score get a high percentile score". I believe this is one of the most arguable point of view about the GMAT. However, I don't know who's right here.

What I really like in the book is page 392. It's a sample GMAT practice test answer sheet, which you can scan and print in many copies for your own test process. It looks pretty nice, except I would prefer to see in a few different layouts, the one which is shown is very tied to original exam format, while I normally take about 40-50 questions per session, grouped by sections and the type of the questions, rarely mixed.

Page 400 opens up a full-length practice test. I run just through 25 questions of quantitative part. Hopefully will finish the rest later tonight or the first tomorrow morning. Wondering about the score.

Monday, August 3, 2009

New names for common things

Okay, so now the Problem Solving chapter at Kaplan's wastebook. Once again, not impressed.

Picking Numbers -- while there is no doubt substituting numbers is a useful technique on GMAT exam, why does every single book published get its own name for it? This drives me mad.

In four examples on using Picking Numbers, I found only two of them (50% if you wish :) appropriate for that technique. I was able to quickly solve the other two with tricking and substituting numbers, but with plain old math.

Backsolving -- I don't know how trustful is that, but sounds intriguing. If it works, I guess this is the first valuable tip so far from this book. Unfortunately, out of 2 examples, I should say only one was appropriate choice. (Still 50% :) The other one could be easily be solved with just "thinking in numbers". Very easy. I'll try Backsolving on some real questions though -- interesting to see how good is that in real life.

Guessing. Damn, while I will guess if I'm stuck -- and this is pretty intuitive -- I would prefer to see some really hardcore question as an example for that, instead of simple proportion of alcohol & water question. What can stuck you there?? The only thing is well stated was Don't guess blindly. I second that.

Basically, that's all you can get from this chapter. Nothing more. You need a separate book to "wake up" your math knowledge. This is one does not give you anything.

I've run the sample 50 questions quiz, scored about 86% correct, I think I will do better with a few tries more and reading the correct answers (which suck by the way! in Kaplan's book). Had a few guesses though (wrong ones :), so need some more concepts to work one.

Next one is Data Sufficiency and I already waiting for the clueless theory part with moderate level of questions coming after it. Good practice anyway, but don't buy, if you ask.

On the other note, I won one of the free tickets to TechCrunch50 2009 that will take place on September 14-15th 2009. I mean, I didn't really get it in my hands, yet, but I don't think that there are any doubts after the confirmation. :)

I don't think I will be make it on Tuesday (and if so, I'll have to leave early, and maybe back afternoon), but I'll be there for Monday. And I would be happy to meet all of you, who're also coming, have some beer or whatever they serve. (Yes, I'm a beer-man.)

Friday, July 31, 2009

GMAT is EZ

I just received two more books EZ Solutions Basic Math for GMAT and Advanced one.

I'm hunting down the high scores on exam. Achieving this from the first try saves me $250 (x times :), so an extra book is never too much. Of course, if it's not dumb and stupid and useless. However, I don't have much people around me to advise.

I had a quick sneak preview of them and it looks like the super practical, however, rather thin ones. Like 3 or 4 times thinner then Kaplan's on Cracking the GMAT books. And, as it often happens, I expect them to be at least 3 times more useful then others. :)

But okay, lets go over the Kaplan's book.

I run through the chapter 4 for a verbal quiz. There were 50 questions which I made 41 correct, giving me 82%. While I don't think that I scored well, as the questions were relatively easy, the most of my mistakes were driven my careless and too much distraction from the side of my email, IM and all other things.

As you can see, I still struggle to put myself into noise-free environment, so I should better learn how to deal with distraction. :)

I didn't really like the explanation part, which is a little bit too messy for me, with no clear points and the answer stated right away, missing the logical path of reaching to it. (Do I ask for too much?)

Sunday, June 14, 2009

Essays and warming up math for GMAT

The last theory part of Cracking the GMAT 2009 was about essays writing (AWA). Overall, it was very okay, I liked it, although it looks like to makes some points controversial to official guide.

Why business schools need AWA on GMAT? They want to protect themselves a little bit against those non-native speakers who actually paid to have their essays written. Well, it might be so.

One of the important points — write as much as you can. Length matters. There is a statistical research that says that the length of essay is related to better score. I believe official GMAT guide says a little bit different things.

While the people who scores the AWA are supposed to ignore minor errors in spelling and grammar, you should be ready them not to. Keep in mind that we're all people and having only 2 minutes for an essay your graders might use to nail down the obvious mistakes only and these are your errors in spelling and grammar.

Pages 326-328 give you a nice template to Analysis of an Issue (AI) part. Don't use it as is though. Make sure to develop your own style or you can be easily caught by an "E-rater" — computerized grader of your essay.

There is a good organizational structure for AI on page 331:
  1. First paragraph to illustrate your understanding of a topic, chosing a position. Restate, express your feeling, but stay limited to couple of sentences.
  2. Second, third and fourth are to develop your examples and ideas to support your thesis.
  3. The last paragraph should sum up your position, but make sure to use slightly different words from the first paragraph.
Make sure to demonstrate a good vocabulary as well as don't go too deeply into finding unsual ideas to support your position. There is a possibility to be graded lower because of missing some obvious points, even if you took a deeper and more educated look at the problem.

Make sure to be specific and stay away from over-generalization.

Next thoughts are about Analysis of an Argument part (AA). Page 335 has a good intro and template for it, as well.

The organizational notes are the following:
  1. First paragraph should sum up the argument's conclusion.
  2. Second, third and fourth are used to attack the argument and supporting evidence.
  3. In the last paragraph you should summarize what you've said and show how the argument could be strengthened.
Starting from page 340 I found a very good ideas on preconstructions. VEry easy things that can be easily used.

On more thing is this is good to use some book to reference your ideas to. While this is not a panacea and not always possible, you might have a recent book or favorite one which you could use.

At the end I went through the warm-up math test which consisted of 20 questions. Unfortunetly, I made 4 mistakes (I was aware about 2 of them and other 2 were careless), but still went into the top one third section and supposed to start from math bins 3 and 4.

Technically, it looks like I'm switching to the hands-on practice again and it'll be less to blog about, except the hard questions.

Monday, March 23, 2009

GMAT PS progress

It's pretty hard to keep up with 50+ questions a day. Sometimes, I found myself spending more then 2 hours for that, what is definitely unacceptable (for the real shot). I'm trying to take my time though to be able to remember all the staff I've already forgot.

While most of the GMAT questions don't go beyond reasonable basic math skills, sometimes some geometric questions are really killing me. Having my last geometries class (I remember about :) more then 12 years ago, it's really a torture to make myself remember all this rules.

What is also rather sad is my correct percentage rate. I'm making a tiny bit more 65% in PS, and I really don't like it. I think this equals to ~42Q, so staying with such numbers, I have to score at least 91% (~40V?) on verbal part to be able to step over 700 score (that's my goal). Scoring 91% on verbal piece sounds pretty tough for me.

Basically, my plan is I have to make at least 90% on quantitative test, so this means I need to get back to the books (which is also pretty tough, because now I need to learn math in English). However, the most of my errors are careless ones, when I'm trying to catch a fast number and don't pay attention to coefficients and signs and whatever not. (But keeping in mind that I'm spending occasionally too much time on these questions that's a pretty poor excuse).

Keeping notes about our weak areas is a good thing. After all, I'm going to prepare some flash cards, and I'll need to know what should they include. Preparing cards during the questions solving time is too much hassle for me, besides, results in duplicates, repeating myself again and again. I'm going to do this some time later, and I'll use the notes posted.

Saturday, February 7, 2009

What is the 20% of 349,000?

What is the 20% of 349,000?

Натолкнулся совершенно случайно. Довольно смешно. Итого, получилось 3 варианта:

а. $69,800
б. $79,800
в. $1,745,000

То-есть пользователю Интернет гораздо легче открыть броузер, зайти на сайт, задать вопрос, подождать ответа, чем открыть калькулятор.

Отвечающие тоже порадовали. Толи еще будет.