Questions about the world of GMAT Math from other sources and general math related questions.
RonPurewal
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Re: Quant Review Q 70. Word Problem Statistics

by RonPurewal Wed Dec 03, 2014 6:28 am

Also, I guess I was afraid that I did not understand the underlying concepts if I used smart numbers, which I now know is not true.


the "underlying concepts" of GMAT math are extremely elementary. there's nothing you need to know beyond first-year high-school algebra and geometry.
if your quant score is ≥ 35, i can pretty much tell you that you already know all the math content that you're ever going to need.
RonPurewal
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Re: Quant Review Q 70. Word Problem Statistics

by RonPurewal Wed Dec 03, 2014 6:34 am

i'm going to quote my own writing above, since this is so important:

RonPurewal Wrote:if you have a possible solution method in mind, DO NOT EVER decide against using it on the basis of "oh, i think that will take too long."[/b]


^^ that.
don't do it.

EVERYONE is absolutely terrible at guessing how long things will take. that's true in general, but it's even more true on this exam—on which the problems are very deliberately engineered not to take a long time.

best example ever: look at OG 13th multiple-choice question #199.

sure, there are clever ways to do this problem with factoring. but you know what else you could try?
good old-fashioned long division.
first, move the decimals to make the bottom numbers into integers (e.g., the left-hand fraction becomes 9999.9999 over 10001).
then, just try long division. if there's a voice in your head saying "that will take too long", just tell the voice to shut up, and start dividing.
you'll be surprised.

... and it's not just that problem. basically every official problem is designed to be, well, not very much work.
throw stuff at the problems; see whether it sticks; repeat.
PetriF258
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Re: Quant Review Q 70. Word Problem Statistics

by PetriF258 Wed Dec 03, 2014 8:57 am

Hi Ron

Thanks for the advice. This has really been a journey. I took my first GMAT exam about a month ago and scored 680 (Q49, V34).

I was so disappointed as I the math was around what I wanted but I was just to tired when I got to verbal. Furthermore, it has been 6 years since I wrote a test!

Anyway, I just want to say thanks as the biggest mistake I made (which I just wish I realized earlier) was to try and get 100% for every single question ans spend way to much time on difficult questions during my preparation. In my opinion the Advanced GMAT quant guide is perfect. It has a bit more difficult questions but not as difficult as some of the crazy questions out there.

And should I get a crazy question which I have no idea of how to answer, just move on. A few crazy questions is not going to be a deal breaker.

Anyways, thanks for the advice and the reason why I attempt to answer other students questions is to deeper my understanding and learn from other people's mistakes / thought processes. Because as a lecturer myself, I know, if you can explain it, you own it.
jnelson0612
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Re: Quant Review Q 70. Word Problem Statistics

by jnelson0612 Sat Dec 06, 2014 10:08 am

Wishing you the best with your studies and test! :-)
Jamie Nelson
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NL
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Re: Quant Review Q 70. Word Problem Statistics

by NL Sat Dec 06, 2014 12:03 pm

RonPurewal Wrote:i didn't actually know that i've influenced you so strongly.


Ah, that's dangerous since you can affect your students in both different ways (ha, I'm joking)

oh, and, about the capital letters, you guys are both wrong. my main laptop has a broken left-hand shift key


Brilliant reason (though I am not sure if it’s true--hehe--am kidding again). This also implies that you can “stand up” in a short time. Cool!

you know how your hearing and proprioception improve when you close your eyes? in the same way, you might find that you write more varied or higher-quality sentences if you don't use caps.


Haha, another good reason. I’ll try it when I’ve done with my gmat and toefl. If I develop that habit now, my essays will be deducted one point.

in any case, we've now completely abandoned any semblance of discussing the GMAT exam in this thread, so, time for me to stop.


Hum, that’s not fair, Guru. You produced a lots of “offspring” that induce my thoughts, then you say: hey, we have to stop here. It’s not different from saying: you can ingest, but “outgest” (hi, I just invented this word for sensitive situations)

But I don’t totally deviate. I learn an RC question here: (just bring stuff from general verbal to general math-sorry)

- What is the author’s purpose when he used the example below?

“when i take questions from students after live classes, i'm usually sitting down (having just been standing for 3 hours). some students stand—even though there are chairs in the vicinity—while others pull up one of the chairs.
i've noticed that the students who pull up the chairs tend to speak to me more as an equal, rather than as "sensei" / "authority figure" (the latter of which i just find awkward). so, there's definitely something to what you're saying.”


A. He implies that “authority figure” attitude is not good for students since stepping out of comfort zones is a way to be better learners. (Sound good. Trap. Dump.)

B. One of the reasons that the student used to persuade Ron to “stand up” in written conversations is not valid. (Tempting. Doubt.)

C. He comforts the student that he/she is ok when he/she is standing while Ron is sitting. (What? Dull. Dump.)

D. He implies that sitting-standing manners are acceptable in some situations such as in classroom. (Ah, that guy looks good)

E. He encourages the student to pull up the chair if he/she participates in Ron’s class. (Hu? Dumb. Dismiss)

--> OA: D

Ok. I agree to stop now.
RonPurewal
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Re: Quant Review Q 70. Word Problem Statistics

by RonPurewal Sat Dec 06, 2014 12:46 pm

ok.