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

It is currently 26 Sep 2018, 03:55

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

The circumference of circle X is 1/2 the circumference of circle Y. Wh

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49496
The circumference of circle X is 1/2 the circumference of circle Y. Wh  [#permalink]

Show Tags

New post 13 Apr 2018, 01:26
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

87% (00:57) correct 13% (01:12) wrong based on 37 sessions

HideShow timer Statistics

The circumference of circle X is 1/2 the circumference of circle Y. What is the area of circle X?

(1) The area of circle Y is \(100\pi\) ft^2.
(2) The circumference of circle Y is \(20\pi\) ft

_________________

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

Manager
Manager
User avatar
G
Joined: 16 Sep 2016
Posts: 240
GMAT 1: 740 Q50 V40
GMAT ToolKit User Premium Member Reviews Badge CAT Tests
Re: The circumference of circle X is 1/2 the circumference of circle Y. Wh  [#permalink]

Show Tags

New post 13 Apr 2018, 01:39
Bunuel wrote:
The circumference of circle X is 1/2 the circumference of circle Y. What is the area of circle X?

(1) The area of circle Y is \(100\pi\) ft^2.
(2) The circumference of circle Y is \(20\pi\) ft


Since we know the relationship between R1 and R2 of the two circles..

2*pi*R2 = 0.5 * 2*pi*R1

Anything that gives R1 will give us R2.

Hence option (D) is our answer without solving for the actual values of anything.

Best,
Gladi

Posted from my mobile device
Intern
Intern
avatar
B
Joined: 31 Jul 2017
Posts: 11
Re: The circumference of circle X is 1/2 the circumference of circle Y. Wh  [#permalink]

Show Tags

New post 13 Apr 2018, 03:15
Answer is B
1 stmt gives 2 output
2 stmt gives correct radius which will be calcuated for Area of Circle X
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6814
Re: The circumference of circle X is 1/2 the circumference of circle Y. Wh  [#permalink]

Show Tags

New post 13 Apr 2018, 03:18
1
rohitf23 wrote:
Answer is B
1 stmt gives 2 output
2 stmt gives correct radius which will be calcuated for Area of Circle X



Yes statement 1 gives two output ..\(r^2 = 100...\) r = 10 or -10
But we are looking at radius and it cannot be NEGATIVE so r = 10
suff
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

Intern
Intern
User avatar
B
Joined: 10 Jan 2017
Posts: 7
Location: India
Concentration: Social Entrepreneurship, General Management
WE: Information Technology (Computer Software)
Re: The circumference of circle X is 1/2 the circumference of circle Y. Wh  [#permalink]

Show Tags

New post 13 Apr 2018, 05:40
1
Cx = 2 pi r
Cy = pi r

Statement 1
Ay=100 pi
also, Ay=C^2/4 pi ==> 100 pi = pi^2 r^2/4 pi ==>r = +/- 20, but radius will be positive so r=20

Statement 2

gives us the same info as statement 1

Cy=20 pi = pi r ==> r=20

Therefore ans is D
Director
Director
avatar
P
Joined: 02 Oct 2017
Posts: 616
Re: The circumference of circle X is 1/2 the circumference of circle Y. Wh  [#permalink]

Show Tags

New post 27 Apr 2018, 22:50
2πx=(1/2)*2πy
X=y/2

1) get value of y using πr^2
Then calculate x
Sufficient

II)get value of y using 2πr
Then calculate x
Sufficient

Answer D

Posted from my mobile device
GMAT Club Bot
Re: The circumference of circle X is 1/2 the circumference of circle Y. Wh &nbs [#permalink] 27 Apr 2018, 22:50
Display posts from previous: Sort by

The circumference of circle X is 1/2 the circumference of circle Y. Wh

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

Events & Promotions

PREV
NEXT


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®.