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

It is currently 14 Dec 2018, 12:08

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • Typical Day of a UCLA MBA Student - Recording of Webinar with UCLA Adcom and Student

     December 14, 2018

     December 14, 2018

     10:00 PM PST

     11:00 PM PST

    Carolyn and Brett - nicely explained what is the typical day of a UCLA student. I am posting below recording of the webinar for those who could't attend this session.
  • Free GMAT Strategy Webinar

     December 15, 2018

     December 15, 2018

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

If a rectangular region has perimeter P inches and area A sq

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

Hide Tags

Manager
Manager
avatar
B
Joined: 23 Dec 2013
Posts: 150
Location: United States (CA)
GMAT 1: 710 Q45 V41
GMAT 2: 760 Q49 V44
GPA: 3.76
Reviews Badge
Re: If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 16 Jul 2017, 10:47
olifurlong wrote:
If a rectangular region has perimeter P inches and area A square inches, is the region square?

(1) P = 4/3*A
(2) P = 4√A


The goal is to determine if the shape is in fact a square.

Statement 1) P = 4/3*(A)

If true, then P=4x and A = x^2

4x = 4/3*(x^2)
x = x^2/3
x = 3

Only true if the side is length 3. We don't know if the side of the shape has length 3, so the statement is insufficient.

Statement 2) P = 4sqrt(A)

4x = 4sqrt(x^2)
4x=4x
x = x

This statement is true, so the statement is sufficient.
Intern
Intern
avatar
B
Joined: 16 Dec 2016
Posts: 8
Location: United States (DC)
GMAT 1: 720 Q47 V42
WE: Consulting (Consulting)
Reviews Badge
Re: If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 17 Jul 2017, 05:47
(B) in IMO. First assume the rectangle is a square. Then l=b. P=4l and Area=l^2. If you consider statement 1, LHS is not equal to RHS.
If you consider statement 2, LHS=RHS. So B is sufficient.
Intern
Intern
avatar
B
Joined: 05 Mar 2015
Posts: 49
Location: Azerbaijan
GMAT 1: 530 Q42 V21
GMAT 2: 600 Q42 V31
GMAT 3: 700 Q47 V38
Re: If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 29 Jan 2018, 03:13
This question raises very important point on DS questions.

First of all it is a YES/NO question.

When you plug in numbers statement (2) becomes YES. And when you plug numbers in statement (2) the answer is almost always no. Theoretically both statements give you concrete YES or NO, therefore each alone must be sufficient.

But two statements must both either say YES or NO. If one statement yields YES but the other NO, then the statement that you know for 100% is sufficient is the correct answer. And there must be at least on set of numbers that would give YES answer for statement one. But you should not bother to find that set of numbers.
Manager
Manager
User avatar
P
Joined: 24 Oct 2016
Posts: 241
GMAT 1: 670 Q46 V36
Re: If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 19 May 2018, 14:41
igotthis wrote:
olifurlong wrote:
If a rectangular region has perimeter P inches and area A square inches, is the region square?
1) P=4/3A
2)P=4√A


Lets try finding the relation between area and perimeter of a square.
We know the area of a square with length x (A) = x^2
The perimeter of the square (P) = 4x

Since P = 4x --> x = P/4

So, A = (P/4)^2
A =(P^2)/16
Therefore, P^2 = 16A
and P = 4*sqrtA

Therefore, B is suff to answer this question


I did the question in a similar way. Could someone please explain why A is not sufficient?

For a square, we know:
A = x^2
P = 4x
A/P = x/4 => P = 4A/x

So shouldn't any equation in that form (i.e. Statement A: P = 4A/3) be sufficient? According to A, our side x would be 3 but I don't think the side would matter since we just need the equation to be in the form P = 4A/x.
_________________

Most Comprehensive Article on How to Score a 700+ on the GMAT (NEW)
Verb Tenses Simplified

If you found my post useful, KUDOS are much appreciated. Giving Kudos is a great way to thank and motivate contributors, without costing you anything.

Board of Directors
User avatar
V
Status: Stepping into my 10 years long dream
Joined: 18 Jul 2015
Posts: 3619
Premium Member Reviews Badge
If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 19 May 2018, 22:41
1
dabaobao wrote:
I did the question in a similar way. Could someone please explain why A is not sufficient?

For a square, we know:
A = x^2
P = 4x
A/P = x/4 => P = 4A/x

So shouldn't any equation in that form (i.e. Statement A: P = 4A/3) be sufficient? According to A, our side x would be 3 but I don't think the side would matter since we just need the equation to be in the form P = 4A/x.


Hey dabaobao ,

You did a very BIG mistake of not reading the question properly.

Question says "If a rectangular region" but you took it a square.

For a rectangle, Perimeter = 2(l+b) and area = l * b.

Now, try substituting the values in statement A, you won't be able to determine whether l = b for the region to be a square. Hence, A is insufficient.

Does that make sense?
_________________

My GMAT Story: From V21 to V40
My MBA Journey: My 10 years long MBA Dream
My Secret Hacks: Best way to use GMATClub | Importance of an Error Log!
Verbal Resources: All SC Resources at one place | All CR Resources at one place
Blog: Subscribe to Question of the Day Blog
GMAT Club Inbuilt Error Log Functionality - View More.
New Visa Forum - Ask all your Visa Related Questions - here.
New! Best Reply Functionality on GMAT Club!
Find a bug in the new email templates and get rewarded with 2 weeks of GMATClub Tests for free
Check our new About Us Page here.

Intern
Intern
avatar
B
Joined: 08 May 2018
Posts: 31
Re: If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 31 Jul 2018, 04:17
olifurlong wrote:
If a rectangular region has perimeter P inches and area A square inches, is the region square?

(1) P = 4/3*A
(2) P = 4√A


Bunuel
chetan2u

I have a small doubt. Can we take the ratio of different units i.e (inches/sq. inches) ?

Perimeter is in inches and Area is in square inches. Per my understanding ratio is independent of units, but shouldn't it (ratio) be obtained for similar units?

Please clarify.
Intern
Intern
avatar
B
Joined: 23 Jul 2018
Posts: 6
If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 07 Aug 2018, 18:06
I have a question:

Even without seeing the (1) or (2), we can prove that this equation needs to be true: \(P = 4\sqrt{A}\).
Proof: If the shape is a square,
    The length of one side should be: \(\sqrt{A}\),
    The perimeter should be: \(P = 4\sqrt{A}\)

We know that the shape can be a square only if the equation above holds. If we are given the information in (1), we could definitely conclude that the shape is NOT a square, since it contradicts the equation above.

So I would think the answer should be D. Can anyone illuminate me about what is wrong in my rationale?
(I know the official answer is not D.)
CEO
CEO
User avatar
D
Joined: 11 Sep 2015
Posts: 3237
Location: Canada
Re: If a rectangular region has perimeter P inches and area A sq  [#permalink]

Show Tags

New post 22 Nov 2018, 08:45
Top Contributor
olifurlong wrote:
If a rectangular region has perimeter P inches and area A square inches, is the region square?

(1) P = (4/3)(A)
(2) P = 4√A

Given: A rectangular region has perimeter P inches and area A square inches

Target question: Is the region square?
This is a good candidate for rephrasing the target question.

So, what kind of relationship between P and A do we need in order for the rectangular region to be a SQUARE?
Well, if the region is a square, then all 4 sides will be the same length
So, if P = the perimeter (sum of all 4 sides), then P/4 = the length of each side
If P/4 = the length of each side, then the AREA = (P/4)(P/4)
In other words: A = (P/4)(P/4)
Simplify: A = P²/16
Multiply both sides by 16 to get: 16A = P²
Take square root of both sides to get: 4√A = P
So, if 4√A = P, then we can be certain that the region is a square.
REPHRASED target question: Does 4√A = P?

Below, you'll find a video with tips on rephrasing the target question

Statement 1: P = (4/3)(A)
Let's TEST some values.
There are several values of P and A that satisfy statement 1. Here are two:
Case a: P = 12 and A = 9. In this case, the answer to the REPHRASED target question is YES, 4√A DOES EQUAL P
Case b: P = 4 and A = 3. In this case, the answer to the REPHRASED target question is NO, 4√A does NOT equal P
Since we cannot answer the REPHRASED target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: P = 4√A
Perfect!!
The answer to the REPHRASED target question is YES, 4√A DOES EQUAL P
Since we can answer the REPHRASED target question with certainty, statement 2 is SUFFICIENT

Answer: B

RELATED VIDEO FROM OUR COURSE

_________________

Test confidently with gmatprepnow.com
Image

GMAT Club Bot
Re: If a rectangular region has perimeter P inches and area A sq &nbs [#permalink] 22 Nov 2018, 08:45

Go to page   Previous    1   2   [ 28 posts ] 

Display posts from previous: Sort by

If a rectangular region has perimeter P inches and area A sq

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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®.