January 22, 2019 January 22, 2019 10:00 PM PST 11:00 PM PST In case you didn’t notice, we recently held the 1st ever GMAT game show and it was awesome! See who won a full GMAT course, and register to the next one. January 26, 2019 January 26, 2019 07:00 AM PST 09:00 AM PST Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.
Author 
Message 
Manager
Joined: 22 Feb 2006
Posts: 91

In the figure, points A, B, C, D, and E lie on a line. A is
[#permalink]
Show Tags
28 Oct 2009, 14:59
Question Stats:
50% (00:39) correct 50% (03:51) wrong based on 237 sessions
HideShow timer Statistics
Attachment:
Q2.jpg [ 6.76 KiB  Viewed 19378 times ]
In the figure, points A, B, C, D, and E lie on a line. A is on both circles, B is the center of the smaller circle, C is the center of the larger circle, D is on the smaller circle, and E is on the larger circle. What is the area of the region inside the larger circle and outside the smaller circle? (1) AB = 3 and BC =2 (2) CD =1 and DE = 4 == Message from the GMAT Club Team == THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION. This discussion does not meet community quality standards. It has been retired. If you would like to discuss this question please repost it in the respective forum. Thank you! To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative  Verbal Please note  we may remove posts that do not follow our posting guidelines. Thank you.
Official Answer and Stats are available only to registered users. Register/ Login.



SVP
Joined: 29 Aug 2007
Posts: 2359

Re: DS: Area between circles
[#permalink]
Show Tags
28 Oct 2009, 17:41
TriColor wrote: In the figure, points A, B, C, D, and E lie on a line. A is on both circles, B is the center of the smaller circle, C is the center of the larger circle, D is on the smaller circle, and E is on the larger circle. What is the area of the region inside the larger circle and outside the smaller circle?
(1) AB = 3 and BC =2 (2) CD =1 and DE = 4
 Please, explain your answer. A. From 1, we know the radii of the circles. SUFF.. From 2, we know the radius of only the large circle. NSF.. Update: Agree with D. Can get the d or r for small circle from 2.
_________________
Verbal: http://gmatclub.com/forum/newtotheverbalforumpleasereadthisfirst77546.html Math: http://gmatclub.com/forum/newtothemathforumpleasereadthisfirst77764.html Gmat: http://gmatclub.com/forum/everythingyouneedtoprepareforthegmatrevised77983.html
GT



Senior Manager
Joined: 18 Aug 2009
Posts: 275

Re: DS: Area between circles
[#permalink]
Show Tags
28 Oct 2009, 19:28
I remember this Q from maybe OG12? and also remember getting this wrong D(A) as mentioned, both radius can be calculated. Area 25pi9pi. Sufficient. (B) CD=1, DE=4, CE, Big circle radius = 5 AC=5 (CA=CE), CD=1, AD > Small circle diameter = 6, radius = 3. Area 25pi9pi. Sufficient.



Math Expert
Joined: 02 Sep 2009
Posts: 52388

Re: DS: Area between circles
[#permalink]
Show Tags
29 Oct 2009, 00:39
I have some doubts about D. I got suspicious because I always beware of tricks when GMAT gives some drawings of figure. How do we know that this figure is drawn to scale? In the figure we see that the point C (center of the bigger circle) is in the smaller circle, BUT it can be outside of it when the small circle diameter is less than the radius of the bigger. In that case: We are still able to answer the question with (1) as it doesn't change a thing for it: sufficient. But for (2) CD = 1 and DE = 4 > R=CD+DE=4+1=5, r=(2RDE)/2=3 > R=5, r=3. OR If C lies outside the smaller circle, CD = 1 and DE = 4. R=DECD=41=3, r=(RCD)/2=(31)/2=1. R=3, r=1. As we have different R and r, the area of the region inside the larger circle and outside the smaller circle would be different in each case. Not sufficient. Answer: A. Probably the most confusing thing here is that when we are dealing with (2) we already know R and r from (1) and it's more difficult to point out the trick, since you get the same R and r for (2) as well and thinking that "OK the same thing sufficient" forgetting to check whether C really lies inside the smaller circle or not.
_________________
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? Extrahard Quant Tests with Brilliant Analytics



Director
Joined: 01 Apr 2008
Posts: 768
Name: Ronak Amin
Schools: IIM Lucknow (IPMX)  Class of 2014

Re: DS: Area between circles
[#permalink]
Show Tags
29 Oct 2009, 00:51
Bunuel:
I am not sure about this...I guess the relative positioning of the points can be trusted even for diagrams. Only the size of line segments and angles can be something which "cant be drawn to scale". For example, if in this diagram we increase or decrease the scale, then also the relative position of points will be the same !



Math Expert
Joined: 02 Sep 2009
Posts: 52388

Re: DS: Area between circles
[#permalink]
Show Tags
29 Oct 2009, 01:05



Manager
Joined: 15 Sep 2009
Posts: 115

Re: DS: Area between circles
[#permalink]
Show Tags
29 Oct 2009, 04:02
statement 1: ========== suff since we know the radius of both the circles.
statement 2: ========== we can find the radius of larger circle. We can also find the diameter of the smaller circle,we can calculate the radius of the smaller circle.
I will choose option D



Senior Manager
Joined: 18 Aug 2009
Posts: 275

Re: DS: Area between circles
[#permalink]
Show Tags
29 Oct 2009, 05:31
@ Economist and Bunuel: I agree with Economist here... Also OA is D. This problem is from OG 12: DS  Q.117



NonHuman User
Joined: 09 Sep 2013
Posts: 9463

Re: In the figure, points A, B, C, D, and E lie on a line. A is
[#permalink]
Show Tags
10 Jul 2018, 20:05
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.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: In the figure, points A, B, C, D, and E lie on a line. A is &nbs
[#permalink]
10 Jul 2018, 20:05






