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

 It is currently 22 Jan 2019, 01:20

### 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

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### The winners of the GMAT game show

January 22, 2019

January 22, 2019

10:00 PM PST

11:00 PM PST

In case you didn’t notice, we recently held the 1st ever GMAT game show and it was awesome! See who won a full GMAT course, and register to the next one.
• ### Key Strategies to Master GMAT SC

January 26, 2019

January 26, 2019

07:00 AM PST

09:00 AM PST

Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.

# Which of the following best approximates the percent by

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Intern
Joined: 07 Feb 2009
Posts: 13
Which of the following best approximates the percent by  [#permalink]

### Show Tags

10 Oct 2010, 02:58
6
4
00:00

Difficulty:

55% (hard)

Question Stats:

65% (01:48) correct 35% (01:54) wrong based on 289 sessions

### HideShow timer Statistics

Which of the following best approximates the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD?

A. 30%
B. 43%
C. 45%
D. 50%
E. 70%
Math Expert
Joined: 02 Sep 2009
Posts: 52378
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

10 Oct 2010, 03:57
1
1
vivaslluis wrote:
Hello,

I've seen the following example that I have doubts to solve:

Which of the following best approximates the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD?
a. 30%
b. 43%
c. 45%
d. 50%
e. 70%

Thank you

Le the side of a square be $$a$$.

Route from A to C along a diagonal AC is $$\sqrt{2}a\approx{1.4a}$$;
Route from A to C around the edge ABC is $$2a$$;

Difference is $$2a-1.4a=0.6a$$ --> $$\frac{0.6a}{2a}=0.3=30%$$.

_________________
Intern
Joined: 07 Feb 2009
Posts: 13
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

10 Oct 2010, 13:44
Great! Thank you!!!
Director
Joined: 23 Apr 2010
Posts: 547
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

27 Nov 2010, 02:19
Could someone please explain to me the wording of the problem? I thought that the phrase:

Quote:
... by which the distance from A to C along a diagonal of square ABCD reduces ...

means 1.4a/2a = 70%

I am a little bit confused here. Thank you.
Manager
Joined: 13 Jul 2010
Posts: 131
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

28 Nov 2010, 10:16
Please read the question carefully, the question says - "..the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD?"

So its not asking what percent the diagonal is of the distance around the edge but rather the percent of the difference between the two distances.

Hope this was helpful.
Manager
Joined: 01 Nov 2010
Posts: 124
Location: Zürich, Switzerland
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

29 Nov 2010, 15:39
Using formula for 45-45-90 triangle, diagonal = sqrt(2) of the each side.

Orion Representative
Joined: 26 Jul 2010
Posts: 343
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

30 Nov 2010, 12:07
Great discussion, everyone - I just want to point out that (fittingly), gettinit gets it! One of the easiest things for the GMAT to do to make a pretty hard problem very hard is to bait you toward answering the wrong question. I've seen them do this a lot with Geometry problems that involve percents - there's a significant but subtle difference between:

Percent OF
and Percent GREATER THAN or LESS THAN

When you see a percentage problem, make sure you pause to answer the right question because pretty much any percent problem could be asked in either way.

For another example that also includes squares and diagonals, you may want to check out: http://www.veritasprep.com/blog/2010/11/gmat-challenge-question-the-squared-circle/
_________________

Brian

Curriculum Developer, Instructor, and Host of Veritas Prep On Demand

Save $100 on live Veritas Prep GMAT Courses and Admissions Consulting Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options. Veritas Prep Reviews Manager Joined: 17 Sep 2010 Posts: 178 Concentration: General Management, Finance GPA: 3.59 WE: Corporate Finance (Entertainment and Sports) Re: Square Diagonal versus Perimeter [#permalink] ### Show Tags 30 Nov 2010, 15:46 1 You could use pythagorean theorem to solve this. x^2+x^2=y^2 All sides of a square are equal, hence the two x^2. Plug in any number and solve. vivaslluis wrote: Hello, I've seen the following example that I have doubts to solve: Which of the following best approximates the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD? a. 30% b. 43% c. 45% d. 50% e. 70% Thank you Orion Representative Joined: 26 Jul 2010 Posts: 343 Re: Square Diagonal versus Perimeter [#permalink] ### Show Tags 30 Nov 2010, 20:08 Hey Trojan, Great call on that - even if you have the x-x-x*sqrt 2 ratio memorized, I think it's important to know where it comes from. In the a^2 + b^2 = c^2 Pythagorean Theorem, if we know that a = b then it's really 2a^2 = c^2. And deriving that for yourself once or twice means there's very little chance you ever forget it (and you know you can always go back and prove it if you do forget). Thanks for bringing that up - I'm a huge fan of knowledge over memorization! _________________ Brian Curriculum Developer, Instructor, and Host of Veritas Prep On Demand Save$100 on live Veritas Prep GMAT Courses and Admissions Consulting

Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.

Veritas Prep Reviews

Manager
Joined: 13 Jul 2010
Posts: 131
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

01 Dec 2010, 18:45
Brian great challenge question post -it fits this question perfectly!

VeritasPrepBrian wrote:
Great discussion, everyone - I just want to point out that (fittingly), gettinit gets it! One of the easiest things for the GMAT to do to make a pretty hard problem very hard is to bait you toward answering the wrong question. I've seen them do this a lot with Geometry problems that involve percents - there's a significant but subtle difference between:

Percent OF
and Percent GREATER THAN or LESS THAN

When you see a percentage problem, make sure you pause to answer the right question because pretty much any percent problem could be asked in either way.

For another example that also includes squares and diagonals, you may want to check out: http://www.veritasprep.com/blog/2010/11/gmat-challenge-question-the-squared-circle/
Intern
Joined: 06 Dec 2012
Posts: 25
Concentration: Finance, International Business
GMAT 1: 510 Q46 V21
GPA: 3.5
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

11 Oct 2013, 05:50
Bunuel wrote:
vivaslluis wrote:
Hello,

I've seen the following example that I have doubts to solve:

Which of the following best approximates the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD?
a. 30%
b. 43%
c. 45%
d. 50%
e. 70%

Thank you

Le the side of a square be $$a$$.

Route from A to C along a diagonal AC is $$\sqrt{2}a\approx{1.4a}$$;
Route from A to C around the edge ABC is $$2a$$;

Difference is $$2a-1.4a=0.6a$$ --> $$\frac{0.6a}{2a}=0.3=30%$$.

Hi ,
i am confused about the denominator in the equation.

if the equation is (2a-1.4a) then the denominator should be 1.4a ???
how it is 2a??? not geeting...
Math Expert
Joined: 02 Sep 2009
Posts: 52378
Re: Square Diagonal versus Perimeter  [#permalink]

### Show Tags

11 Oct 2013, 05:53
sunny3011 wrote:
Bunuel wrote:
vivaslluis wrote:
Hello,

I've seen the following example that I have doubts to solve:

Which of the following best approximates the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD?
a. 30%
b. 43%
c. 45%
d. 50%
e. 70%

Thank you

Le the side of a square be $$a$$.

Route from A to C along a diagonal AC is $$\sqrt{2}a\approx{1.4a}$$;
Route from A to C around the edge ABC is $$2a$$;

Difference is $$2a-1.4a=0.6a$$ --> $$\frac{0.6a}{2a}=0.3=30%$$.

Hi ,
i am confused about the denominator in the equation.

if the equation is (2a-1.4a) then the denominator should be 1.4a ???
how it is 2a??? not geeting...

We are comparing to the route from A to C around the edge, which is 2a, so 2a must be in the denominator.
_________________
VP
Joined: 05 Mar 2015
Posts: 1003
Re: Which of the following best approximates the percent by  [#permalink]

### Show Tags

31 May 2016, 20:04
vivaslluis wrote:
Which of the following best approximates the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD?

A. 30%
B. 43%
C. 45%
D. 50%
E. 70%

let the sides be 2 units.
original distance=2+2=4units
changed distance=2sq.root2
%change=change dist.-original dist./original dist.
=(2sq.root2-4)/4==-.2955
reduced by ~30%
Ans A
Director
Joined: 14 Dec 2017
Posts: 524
Location: India
Re: Which of the following best approximates the percent by  [#permalink]

### Show Tags

03 Aug 2018, 10:51
vivaslluis wrote:
Which of the following best approximates the percent by which the distance from A to C along a diagonal of square ABCD reduces the distance from A to C around the edge of square ABCD?

A. 30%
B. 43%
C. 45%
D. 50%
E. 70%

Let $$a$$ be the length of the side of the square, hence the diagonal is $$\sqrt{2}a$$ = $$1.4 a$$

Length along the edge of the square = $$2a$$

Hence the % by which the distance is reduced along the diagonal = $$\frac{(2a - 1.4a)}{2a}$$ = $$\frac{0.7}{2}$$ =~ $$0.3$$ = 30%

Thanks,
GyM
_________________
Re: Which of the following best approximates the percent by &nbs [#permalink] 03 Aug 2018, 10:51
Display posts from previous: Sort by

# Which of the following best approximates the percent by

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.