GMAT Changed on April 16th - Read about the latest changes here

It is currently 26 Apr 2018, 04:45

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

Events & Promotions in June
Open Detailed Calendar

Triangles ABC and BCD are each isosceles. If a = 40, what is the value

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 44656
Triangles ABC and BCD are each isosceles. If a = 40, what is the value [#permalink]

Show Tags

New post 29 Nov 2015, 10:48
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

90% (00:39) correct 10% (00:43) wrong based on 61 sessions

HideShow timer Statistics

Image
Triangles ABC and BCD are each isosceles. If a = 40, what is the value of y?

A. 40
B. 45
C. 50
D. 55
E. 60

[Reveal] Spoiler:
Attachment:
Isosceles_Pair.png
Isosceles_Pair.png [ 6.71 KiB | Viewed 1429 times ]
[Reveal] Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

SC Moderator
User avatar
P
Joined: 13 Apr 2015
Posts: 1620
Location: India
Concentration: Strategy, General Management
WE: Analyst (Retail)
GMAT ToolKit User Premium Member CAT Tests
Re: Triangles ABC and BCD are each isosceles. If a = 40, what is the value [#permalink]

Show Tags

New post 29 Nov 2015, 10:55
a = 40
a + 2x = 180 --> x = 70

x + 2y = 180 --> y = 55

Answer: D
Verbal Forum Moderator
User avatar
V
Status: Greatness begins beyond your comfort zone
Joined: 08 Dec 2013
Posts: 1963
Location: India
Concentration: General Management, Strategy
Schools: Kelley '20, ISB '19
GPA: 3.2
WE: Information Technology (Consulting)
GMAT ToolKit User Reviews Badge CAT Tests
Triangles ABC and BCD are each isosceles. If a = 40, what is the value [#permalink]

Show Tags

New post 29 Nov 2015, 11:37
In \(\triangle\) ABC ,
=> a +2x= 180
Since a=40
x= 70

In \(\triangle\) BCD,
=>x+2y =180
=>y=55

Answer D
_________________

When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry Ford
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long
+1 Kudos if you find this post helpful

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 44656
Re: Triangles ABC and BCD are each isosceles. If a = 40, what is the value [#permalink]

Show Tags

New post 01 Jan 2018, 11:50
Bunuel wrote:
Image
Triangles ABC and BCD are each isosceles. If a = 40, what is the value of y?

A. 40
B. 45
C. 50
D. 55
E. 60

[Reveal] Spoiler:
Attachment:
Isosceles_Pair.png


VERITAS PREP OFFICIAL SOLUTION:

One extremely helpful tool that you’ll often find in your geometry toolkit is the presence of isosceles triangles. Here, once you’ve filled in 40 for angle a, you should notice that even though there are two angles remaining to solve for within triangle ABC, those two angles each equal the same thing. So since the sum of all three has to be 180, and angle a already accounts for 40, 2x has to equal the remaining 140. 2x = 140 means that x = 70. And then you get to use the same logic all over again. Within triangle BCD, you know that x = 70 and that the sum of the three angles must be 180. That means that 2y = 110, so y = 55, answer choice D.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Re: Triangles ABC and BCD are each isosceles. If a = 40, what is the value   [#permalink] 01 Jan 2018, 11:50
Display posts from previous: Sort by

Triangles ABC and BCD are each isosceles. If a = 40, what is the value

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


GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.