It is currently 17 Oct 2017, 15:37

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

The diagram shows circular sections of a cone. If x is 20 percent of R

  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: 41873

Kudos [?]: 128601 [0], given: 12180

The diagram shows circular sections of a cone. If x is 20 percent of R [#permalink]

Show Tags

New post 05 Oct 2017, 06:07
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

54% (01:29) correct 46% (01:01) wrong based on 25 sessions

HideShow timer Statistics

Image
The diagram shows circular sections of a cone. If x is 20 percent of R, by what percentage is the area of circle C greater than the area of circle B? (Note: Figure not drawn to scale)

A. 250%
B. 400%
C. 500%
D. 2400%
E. 2500%

[Reveal] Spoiler:
Attachment:
Cone.png
Cone.png [ 20.91 KiB | Viewed 312 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

Kudos [?]: 128601 [0], given: 12180

Senior Manager
Senior Manager
avatar
S
Joined: 22 Aug 2013
Posts: 432

Kudos [?]: 130 [0], given: 260

Location: India
Re: The diagram shows circular sections of a cone. If x is 20 percent of R [#permalink]

Show Tags

New post 05 Oct 2017, 06:42
So basically we have two circles, radius of smaller circle is 20% of radius of larger circle. Let radius of bigger circle = 10, then radius of smaller circle = 2.

Ratio of their areas = pi (10)^2 / pi (2)^2 = 25:1

Since area of bigger circle is 25 times that of smaller circle, it is 2400% more than smaller area. Hence D answer

Kudos [?]: 130 [0], given: 260

Manager
Manager
avatar
B
Joined: 20 Jan 2016
Posts: 197

Kudos [?]: 12 [0], given: 63

Re: The diagram shows circular sections of a cone. If x is 20 percent of R [#permalink]

Show Tags

New post 06 Oct 2017, 08:12
I will go with E

x=0.2R
Say R=10
therefore, x=2

Area of R= 314
Area of B= 12.56

Increased percentage = (301/12.56). 100
This is approximately equal to 2500%

E

Kudos [?]: 12 [0], given: 63

Director
Director
avatar
P
Joined: 22 May 2016
Posts: 802

Kudos [?]: 253 [0], given: 544

The diagram shows circular sections of a cone. If x is 20 percent of R [#permalink]

Show Tags

New post 06 Oct 2017, 11:54
Bunuel wrote:
Image
The diagram shows circular sections of a cone. If x is 20 percent of R, by what percentage is the area of circle C greater than the area of circle B? (Note: Figure not drawn to scale)

A. 250%
B. 400%
C. 500%
D. 2400%
E. 2500%

[Reveal] Spoiler:
Attachment:
Cone.png

The cone does not matter; all we need are areas of two circles.

Choose values

Let R = 5
Let x = 1 (20 percent of 5)

Area of Circle C = \(25\pi\)
Area of Circle B = \(1\pi\)

By what percentage is the area of circle C greater than the area of circle B?

Percent increase = \(\frac{(New - Old)}{Old} * 100\)

\(\frac{(25\pi - 1\pi)}{1\pi} * 100\)

\(\frac{24}{1} * 100\) = 2400 percent

Circle C's area is 2400 percent greater than Circle B's area

ANSWER D

Use multiplier / scale factor
x = .20R

Area of Circle C = \(\pi*R^2\)

Let area of C, \(\pi*R^2 = X\)

Area of Circle B =
(scale factor)\(^2\) * (Area of C)

\((.2)^2(X) =.04X =\)Area of B

Percent increase =

\(\frac{(X) - (.04X)}{(.04X)} * 100\)

\(\frac{.96X}{.04X} = (24 * 100)\) = 2400 percent

Answer D

Kudos [?]: 253 [0], given: 544

The diagram shows circular sections of a cone. If x is 20 percent of R   [#permalink] 06 Oct 2017, 11:54
Display posts from previous: Sort by

The diagram shows circular sections of a cone. If x is 20 percent of R

  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®.