GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 14 Oct 2019, 04:35

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# General question regarding parenthesis.

Author Message
TAGS:

### Hide Tags

Intern
Joined: 07 May 2015
Posts: 7

### Show Tags

09 May 2015, 10:07
1
Hi there,

I have a question regarding the use of parenthesis and dividing/multiplication.

As an example:
$$(1,5 * 10^3) / (0,5 * 10^6) = (1,5 / 0,5) * (10^3 / 10^6)$$

Why can you just switch $$10^3$$ with $$0,5$$ and then switch the dividing and multiplication signs. I have no idea when to
use methods or apply rules like this so if anyone has an explanation
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15240
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

09 May 2015, 10:53
Hi MarcvR,

It sounds like you're interested in broader PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction) rules. These rules dictate the order in which you have to do calculations.

In the prompt you've provided, no calculations have actually been done - the prompt has just been re-written (and it's worth noting that the 10^3 and 0.5 were NOT "switched").

Notice how the numbers in both the numerator and denominator are MULTIPLIED. This means that we can re-write the fraction in a variety of different ways. The example that you listed is complex-looking, so I'm going to show you some simpler examples:

(1/2)(3/5) can be rewritten in any of the following ways (notice that the end calculation is always the SAME):

(1/2)(3/5) = 3/10

(1x3)/(2x5) = 3/10

(3x1)/(5x2) = 3/10

(1/5)(3/2) = 3/10

The same rules apply to the example that you listed. It might be that you just need more practice with hands-on calculations.

How long have you been studying?
What resources have you been using?
When are you planning to take the GMAT?

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
GMAT Tutor
Joined: 24 Jun 2008
Posts: 1810
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

09 May 2015, 10:54
1
Here, you're just using the rule for multiplying fractions, but in reverse. You have probably learned that:

$$\left( \frac{a}{b} \right) \left( \frac{c}{d} \right) = \frac{ac}{bd}$$

This rule works in both directions; if we have something that looks like the left side, we can rewrite it to look like the right side, and vice versa. In your example, you start with something that looks like the right side of the equation above, and have rewritten it to look like the left side.
_________________
GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com
Intern
Joined: 07 May 2015
Posts: 7
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

10 May 2015, 06:03
Thanks for the great help both!

Based on your information I can apply and understand the rules for this question. I have a lot of problems with recognizing a question and apply the right rule to it. But I believe that a lot of practice will get me to the right spot.

EMPOWERgmatRichC
How long have you been studying?
I have been studying for like 2/3 months (with the last month hardcore) but I primarily focussed on verbal until now.

What resources have you been using?
The website gmatcursus.nl. It is a website where you have 15 chapters with video lessons for both Quantative and Verbal, a random test generator
My goal score is 680-700

When are you planning to take the GMAT?
I want to take the test around the 3th of June so if I fail the first time I can retry it around 3 more times before school starts.
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15240
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

10 May 2015, 10:25
Hi MarcvR,

Have you taken any FULL-LENGTH practice CATs yet? If so, then what were your scores (including the Quant and Verbal Scaled Scores)?

Based on what you've described, you might not have given yourself enough time to score at the desired level by June 3rd. I would never have you 'rush in' to take the GMAT if you didn't feel ready. By your own admission, if you have the room in your calendar to take the GMAT multiple times, then you could push back this Test Date, study some more and save some money.

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Intern
Joined: 07 May 2015
Posts: 7
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

11 May 2015, 01:56
Hi Rich,

I took one CAT-test so far but it did not include the AWA section. I scored 540 on the first try with 4 out of 12 IR, 21 out of 37 Q and 25 out of 41 V. The scores: 3 IR, 33Q and 31V. I have no idea why I scored higher on quantative by the way..

Maybe you are right and I should push it back a week or two. First I am going to complete all my quantative lessons and read all about the AWA on this forum. Then I am going to take all the CAT-test (3) that I have left. Then I am going to take the first real G-mat where I hope to score atleast 600. If I still have a few weeks before school starts I will consider to study more and get a higher score.

But let's first try to get control of the quantative section!
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15240
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

11 May 2015, 11:38
Hi MarcvR,

When it comes to properly preparing to face the Official GMAT, there is NO substitute for taking FULL-LENGTH CATs in a realistic and test-like fashion. When you take your next CAT, you MUST take the FULL CAT in one sitting in a way that matches Test Day in as many details as you can reasonably control.

Endurance and fatigue issues are aspects of the the GMAT that some Test Takers do not properly prepare for. Then, on Test Day, they aren't ready to face those issues and get 'killed.' The GMAT is a remarkably consistent and predictable Exam, so you CAN make your practice match. By putting in the extra effort and training now, you'll find Test Day to be easier to deal with.

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Intern
Joined: 07 May 2015
Posts: 7
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

12 May 2015, 02:12
Hi Rich,

Thanks again for the advice! The CAT-test that I have access to right now doesn't include the AWA.
When I have the feeling I practiced enough, I will find and take a full CAT-test to see how I perform.
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15240
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

12 May 2015, 20:48
Hi MarcvR,

Taking FULL-LENGTH CATs is an essential part of the training process. There are things that you can learn ONLY by taking FULL CATs under realistic and test-like conditions (things that you will need to work on to improve).

I highly recommend that you take a FULL CAT soon (you can download 2 for free from www.mba.com). Those score results are the only way to know if you're truly ready to take the GMAT on June 3rd.

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Non-Human User
Joined: 09 Sep 2013
Posts: 13093
Re: General question regarding parenthesis.  [#permalink]

### Show Tags

29 Jan 2018, 00:05
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: General question regarding parenthesis.   [#permalink] 29 Jan 2018, 00:05
Display posts from previous: Sort by