Find all School-related info fast with the new School-Specific MBA Forum

It is currently 27 Nov 2014, 01:36

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

In the figure above, what is the value of x + y ?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
avatar
Joined: 28 Jul 2011
Posts: 582
Location: United States
Concentration: International Business, General Management
GPA: 3.86
WE: Accounting (Commercial Banking)
Followers: 1

Kudos [?]: 62 [0], given: 16

In the figure above, what is the value of x + y ? [#permalink] New post 28 Dec 2011, 06:48
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

71% (01:31) correct 29% (00:32) wrong based on 66 sessions
Attachment:
OG-DS-140.png
OG-DS-140.png [ 9.11 KiB | Viewed 4456 times ]
In the figure above, what is the value of x + y ?

(1) x = 70
(2) ΔABC and ΔADC are both isosceles triangles.

I thought the answer is A

here is my reasoning

From 1.From the Figure As per triangles property when x=70 then Y=140, i.e Inscribed angle = twice the central angle...But In the Answer it says Y can vary.....

From 2. as we don't have any sides or angles we can't get anything from here

So I thought the answer is A..But surprisingly the answer is E.......

Can anyone please explain,How is it so.....

Thanks in advance
[Reveal] Spoiler: OA

_________________

+1 Kudos If found helpful..

Expert Post
2 KUDOS received
Magoosh Co-Founder
User avatar
Joined: 17 Sep 2011
Posts: 40
Schools: UC Berkeley (Haas) - Class of 2010
Followers: 17

Kudos [?]: 23 [2] , given: 12

Re: Geometry(Official Guide 12th Edition #Q140 DS) [#permalink] New post 28 Dec 2011, 07:53
2
This post received
KUDOS
Expert's post
Answer is E

Here's a rough version of the image.
Image

Statement 1 is insufficient.
We know angle x is 70, but we know nothing about the placement of point D. The lower the placement of point D the greater the angle y, so y could really be any number of values. Remember we can't assume anything about the placement of a point, unless we are explicitly told about the placement in the question.

Statement 2 is insufficient.
x and y could be any number of values. For instance x could be 50 degrees or 70 degrees. All we know is that the triangles are isosceles, but we know nothing about the angles.

Statements 1 and 2 together are insufficient.
From statement 1 we know x is 70 and that angles BAC and BCA are both 55. But again we know nothing about the placement of point D. Point D could be very close to B in which case y would be close to 70 degrees or point D could be close to the segment AC in which case y would be close to 180 degrees.

I hope that helps!
Bhavin
_________________

Bhavin Parikh
Magoosh Test Prep

Image

Image

Intern
Intern
avatar
Joined: 21 Feb 2012
Posts: 12
Location: Chile
Followers: 0

Kudos [?]: 6 [0], given: 3

Re: Geometry(Official Guide 12th Edition #Q140 DS) [#permalink] New post 21 Apr 2012, 08:16
The OG explanation assumes that given that the triangles are isosceles, then the pairs of sides that are equal are (AB, BC) and (AD, DC). Why OG does that!? I think we cannot assume anything regarding which side is the base of each triangle.
_________________

Francisco

Manager
Manager
avatar
Joined: 06 May 2012
Posts: 77
Followers: 2

Kudos [?]: 17 [0], given: 16

Re: Geometry(Official Guide 12th Edition #Q140 DS) [#permalink] New post 21 Jun 2012, 16:44
fcomorales wrote:
The OG explanation assumes that given that the triangles are isosceles, then the pairs of sides that are equal are (AB, BC) and (AD, DC). Why OG does that!? I think we cannot assume anything regarding which side is the base of each triangle.


You are correct. Unless there is some information about which side is base, it shouldn't assume that AB, BC and AD, DC are equal.

My take,

1 - Even if x=70, there is no information given about the placement of point D / the relation between the triangles - INSUFFICIENT
2 - Two triangles are isosceles. We cannot determine which two sides are equal and cannot determine the values of x & y. - INSUFFICIENT

1 & 2 combined together are also not sufficient.

Answer - E
Senior Manager
Senior Manager
User avatar
Joined: 28 Mar 2012
Posts: 287
Concentration: Entrepreneurship
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
Followers: 16

Kudos [?]: 184 [0], given: 23

GMAT ToolKit User
Re: In the figure above, what is the value of x + y ? [#permalink] New post 22 Jun 2012, 00:31
Hi Kotela,

I have a question for you. Lets say x = 70, y = 140, will D be the center of the center of circle passing through A, B & C? Think! 8-)

Regards,

kotela wrote:
Attachment:
OG-DS-140.png
In the figure above, what is the value of x + y ?

(1) x = 70
(2) ΔABC and ΔADC are both isosceles triangles.

I thought the answer is A

here is my reasoning

From 1.From the Figure As per triangles property when x=70 then Y=140, i.e Inscribed angle = twice the central angle...But In the Answer it says Y can vary.....

From 2. as we don't have any sides or angles we can't get anything from here

So I thought the answer is A..But surprisingly the answer is E.......

Can anyone please explain,How is it so.....

Thanks in advance

_________________

My posts: Solving Inequalities, Solving Simultaneous equations, Divisibility Rules

My story: 640 What a blunder!

Vocabulary resource: EdPrep

Facebook page: fb.com/EdPrep

Re: In the figure above, what is the value of x + y ?   [#permalink] 22 Jun 2012, 00:31
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic In the figure above, what is the value of x? fozzzy 4 03 Sep 2013, 23:44
14 In the figure above, what is the value of x? emmak 5 25 Mar 2013, 21:57
9 Experts publish their posts in the topic What is the value of x + y in the figure above? Walkabout 2 26 Dec 2012, 04:18
8 Experts publish their posts in the topic In the figure above, what is the value of x + y ? Walkabout 22 18 Dec 2012, 05:08
6 Experts publish their posts in the topic What is the value of x+y in the figure above? Baten80 5 08 Mar 2011, 13:16
Display posts from previous: Sort by

In the figure above, what is the value of x + y ?

  Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group and phpBB SEO

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®.