Last visit was: 31 Oct 2024, 16:00 It is currently 31 Oct 2024, 16:00
Home
MBA Fair
MBA Fair
GMAT
Messages
Tests
Schools
Reviews
Chat
My Profile
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
555-605 Level|   Geometry|      
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 31 Oct 2024
Posts: 96,533
Own Kudos:
673,098
 [4]
Given Kudos: 87,883
Products:
GMAT Club Tests Forum Quiz
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 96,533
Kudos: 673,098
 [4]
A rectangular circuit board is designed to have a width of W inches, a   05 Dec 2014, 07:34
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

25% (medium)

Question Stats:

77% (02:01) correct 23% (02:14) wrong based on 148 sessions

History

Date
Time
Result
Not Attempted Yet

Tough and Tricky questions: Geometry.



A rectangular circuit board is designed to have a width of W inches, a length of L inches, a perimeter of P inches, and an area of A square inches. Which of the following equations must be true?

A) 2W^2 + PW + 2A = 0
B) 2W^2 − PW + 2A = 0
C) 2W^2 − PW − 2A = 0
D) W^2 + PW + A = 0
E) W^2 − PW + 2A = 0

Kudos for a correct solution.

Source: Chili Hot GMAT
ShowHide Answer
Official Answer
B
User avatar
manpreetsingh86
User avatar
Joined: 13 Jun 2013
Last visit: 19 Dec 2022
Posts: 222
Own Kudos:
1,085
 [3]
Given Kudos: 14
Posts: 222
Kudos: 1,085
 [3]
A rectangular circuit board is designed to have a width of W inches, a   05 Dec 2014, 11:24
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel

Tough and Tricky questions: Geometry.



A rectangular circuit board is designed to have a width of W inches, a length of L inches, a perimeter of P inches, and an area of A square inches. Which of the following equations must be true?

A) 2W^2 + PW + 2A = 0
B) 2W^2 − PW + 2A = 0
C) 2W^2 − PW − 2A = 0
D) W^2 + PW + A = 0
E) W^2 − PW + 2A = 0

Kudos for a correct solution.

Source: Chili Hot GMAT

P = 2(L+W)-----------------1)
A= LW------------------------2)

option A is not possible why ?? because all the terms are positive.
lets try option B , put value of P and A from 1 and 2 we have,
2W^2-2(L+W)W + 2(LW)
2W^2 - 2LW - 2W^2 + 2LW=0.

hence answer is B.
avatar
intheend14
avatar
Joined: 12 Sep 2014
Last visit: 08 Sep 2019
Posts: 127
Own Kudos:
140
 [1]
Given Kudos: 103
Concentration: Strategy, Leadership
Schools: Stanford '18 Haas '18 Wharton '18 Kellogg PT '18 Insead Sept '16
GMAT 1: 740 Q49 V41
GPA: 3.94
Schools: Stanford '18 Haas '18 Wharton '18 Kellogg PT '18 Insead Sept '16
GMAT 1: 740 Q49 V41
Posts: 127
Kudos: 140
 [1]
A rectangular circuit board is designed to have a width of W inches, a   05 Dec 2014, 11:32
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Choice B is the answer.

We know area = w*l and perimeter = 2w + 2l
Let's see what some of these terms equal to: 2w^2 = 2w^2, pw = 2w^2 + 2wl and a = w*l
We need all the terms to cancel out and we can see that each term in pw goes with either area or 2w^2, so we probably need either pw to be negative or 2A and 2W^2 to be negative--Choice B does this

2w^2 -pw + 2A = 2w^2 - 2w^2 - 2wl + 2wl, which all cancels out.

B
User avatar
arunspanda
User avatar
Joined: 04 Oct 2013
Last visit: 31 Oct 2021
Posts: 127
Own Kudos:
310
 [1]
Given Kudos: 55
Location: India
GMAT Date: 05-23-2015
GPA: 3.45
Products:
My Reviews
Posts: 127
Kudos: 310
 [1]
A rectangular circuit board is designed to have a width of W inches, a   Updated on: 05 Dec 2014, 13:31
Originally posted by arunspanda on 05 Dec 2014, 11:57.
Last edited by arunspanda on 05 Dec 2014, 13:31, edited 1 time in total.
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
A rectangular circuit board is designed to have a width of W inches, a length of L inches, a perimeter of P inches, and an area of A square inches. Which of the following equations must be true?

A) 2W^2 + PW + 2A = 0
B) 2W^2 − PW + 2A = 0
C) 2W^2 − PW − 2A = 0
D) W^2 + PW + A = 0
E) W^2 − PW + 2A = 0


Perimeter of the circuit board , \(P = 2W + 2L\)

As all the answer choices are in terms of A, P and W, let us express L in terms of P and W

\(L = \frac{P}{2} - W\)

Substituting the above value of L in equation \(2A = 2*W*L\),

\(2A = 2*(W*L) = 2* W *( \frac{P}{2}-W)\)

Or, \(2A = WP - 2W^2\)

Or, \(2W^2 -WP+2A =0\)

Answer: B
User avatar
manpreetsingh86
User avatar
Joined: 13 Jun 2013
Last visit: 19 Dec 2022
Posts: 222
Own Kudos:
1,085
 [1]
Given Kudos: 14
Posts: 222
Kudos: 1,085
 [1]
A rectangular circuit board is designed to have a width of W inches, a   05 Dec 2014, 13:04
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
arunspanda
A rectangular circuit board is designed to have a width of W inches, a length of L inches, a perimeter of P inches, and an area of A square inches. Which of the following equations must be true?

A) 2W^2 + PW + 2A = 0
B) 2W^2 − PW + 2A = 0
C) 2W^2 − PW − 2A = 0
D) W^2 + PW + A = 0
E) W^2 − PW + 2A = 0


Perimeter of the circuit board , \(P = 2W + 2L\)

As all the answer choices are in terms of A, P and W, let us express L in terms of P and W

\(L = \frac{P}{2} - W\)

Substituting the above value of L in equation \(2A = 2*W*L\),

\(2A = 2*(W*L) = 2* W *( \frac{P}{2}-W)\)

Or, \(2A = WP - 2W^2\)

Or, \(2W^2 -WP+2A =0\)

Answer: E

Highlight portion is option B not E.
avatar
mridupawandas
avatar
Joined: 02 May 2014
Last visit: 01 Feb 2017
Posts: 95
Own Kudos:
46
 [1]
Given Kudos: 46
Status:Applied
Location: India
Concentration: Operations, General Management
Schools: Terry '18 (WL) Katz '18 (D) Tippie '18 (D) Eller FT'18 (A) Schulich Sept"18 (S) Desautels '18 (I) Sauder '18 (S) Olin '18 (S) Neeley '18 (WL) Tulane '18 (A) Moore '18 Fox(Temple)'18 UCSD '18 Weatherhead '18 (S) GWU '18 Simon '18 Madison '18
GMAT 1: 690 Q47 V38
GPA: 3.35
WE:Information Technology (Computer Software)
Schools: Terry '18 (WL) Katz '18 (D) Tippie '18 (D) Eller FT'18 (A) Schulich Sept"18 (S) Desautels '18 (I) Sauder '18 (S) Olin '18 (S) Neeley '18 (WL) Tulane '18 (A) Moore '18 Fox(Temple)'18 UCSD '18 Weatherhead '18 (S) GWU '18 Simon '18 Madison '18
GMAT 1: 690 Q47 V38
Posts: 95
Kudos: 46
 [1]
A rectangular circuit board is designed to have a width of W inches, a   06 Dec 2014, 08:16
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
p=2l+2w
a=lw
putting the values in option B we get as follows
2w^2-w(2l+2w)+2lw=2w^2-2lw-2w^2+2lw=0

Hence proved.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 31 Oct 2024
Posts: 96,533
Own Kudos:
673,098
Given Kudos: 87,883
Products:
GMAT Club Tests Forum Quiz
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 96,533
Kudos: 673,098
A rectangular circuit board is designed to have a width of W inches, a   08 Dec 2014, 06:03
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel

Tough and Tricky questions: Geometry.



A rectangular circuit board is designed to have a width of W inches, a length of L inches, a perimeter of P inches, and an area of A square inches. Which of the following equations must be true?

A) 2W^2 + PW + 2A = 0
B) 2W^2 − PW + 2A = 0
C) 2W^2 − PW − 2A = 0
D) W^2 + PW + A = 0
E) W^2 − PW + 2A = 0

Kudos for a correct solution.

Source: Chili Hot GMAT

The correct answer is B.
avatar
PareshGmat
avatar
Joined: 27 Dec 2012
Last visit: 10 Jul 2016
Posts: 1,552
Own Kudos:
7,436
Given Kudos: 193
Status:The Best Or Nothing
Location: India
Concentration: General Management, Technology
WE:Information Technology (Computer Software)
Posts: 1,552
Kudos: 7,436
A rectangular circuit board is designed to have a width of W inches, a   08 Dec 2014, 23:22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
p = 2w + 2l ............ (1)

a = wl

Looking at the OA, we see that "l" is not present. Hence replacing \(l = \frac{a}{w}\) in equation (1)

\(p = 2w + 2\frac{a}{w}\)

\(pw = 2w^2 + 2a\)

\(2w^2 + 2a - pw = 0\)

Answer = B
avatar
mathiaskeul
avatar
Joined: 10 Apr 2016
Last visit: 16 May 2016
Posts: 50
Own Kudos:
25
Given Kudos: 7
Concentration: Strategy, Entrepreneurship
GMAT 1: 520 Q29 V30
GPA: 3.01
GMAT 1: 520 Q29 V30
Posts: 50
Kudos: 25
A rectangular circuit board is designed to have a width of W inches, a   18 Apr 2016, 06:09
Kudos
Add Kudos
Bookmarks
Bookmark this Post
i just plugged it in real quick
l 2
w 4
a 8
p 12

Started with D, which immediatly made it clear that I need 2 times A within the same formula to get 0. This lead me to B.

Ans B
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 35,330
Own Kudos:
902
Posts: 35,330
Kudos: 902
A rectangular circuit board is designed to have a width of W inches, a   28 Aug 2022, 19:29
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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.
Moderator:
Bunuel
Math Expert
96533 posts