It is currently 25 Feb 2018, 07:42

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

If the circle above has center O and circumference 18m, then the perim

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

Hide Tags

Top Contributor
Board of Directors
User avatar
G
Joined: 01 Sep 2010
Posts: 3483
If the circle above has center O and circumference 18m, then the perim [#permalink]

Show Tags

New post 21 May 2017, 10:39
Top Contributor
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

83% (00:45) correct 17% (01:00) wrong based on 58 sessions

HideShow timer Statistics

Image

If the circle above has center O and circumference 18π, then the perimeter of sector RSTO Is

(A) 3π + 9

(B) 3π + 18

(C) 6π + 9

(D) 6π + 18

(E) 6π + 24


[Reveal] Spoiler:
Attachment:
6p5jvHu.jpg
6p5jvHu.jpg [ 10.49 KiB | Viewed 1327 times ]
[Reveal] Spoiler: OA

_________________

COLLECTION OF QUESTIONS AND RESOURCES
Quant: 1. ALL GMATPrep questions Quant/Verbal 2. Bunuel Signature Collection - The Next Generation 3. Bunuel Signature Collection ALL-IN-ONE WITH SOLUTIONS 4. Veritas Prep Blog PDF Version 5. MGMAT Study Hall Thursdays with Ron Quant Videos
Verbal:1. Verbal question bank and directories by Carcass 2. MGMAT Study Hall Thursdays with Ron Verbal Videos 3. Critical Reasoning_Oldy but goldy question banks 4. Sentence Correction_Oldy but goldy question banks 5. Reading-comprehension_Oldy but goldy question banks


Last edited by Bunuel on 21 May 2017, 10:49, edited 3 times in total.
Edited the question.
Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43904
Re: If the circle above has center O and circumference 18m, then the perim [#permalink]

Show Tags

New post 21 May 2017, 10:48
1
This post received
KUDOS
Expert's post
carcass wrote:
Image

If the circle above has center O and circumference 18π, then the perimeter of sector RSTO Is

(A) 3π + 9

(B) 3π + 18

(C) 6π + 9

(D) 6π + 18

(E) 6π + 24


[Reveal] Spoiler:
Attachment:
6p5jvHu.jpg


The perimeter of of sector RSTO is (radius OR) + (radius OT) + (minor arc RT).

The circumference is \(18\pi\): \(2\pi{r}=18\pi\) --> \(r=9\);

Since angle ROT is 60 degrees then minor arc RT is \(\frac{60}{360}*circumference=3\pi\);

So, the perimeter of sector RSTO is (radius OR) + (radius OT) + (minor arc RT) = \(9+9+3\pi=3\pi+18\).

Answer: B.
_________________

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

Director
Director
User avatar
P
Joined: 04 Dec 2015
Posts: 696
Location: India
Concentration: Technology, Strategy
Schools: ISB '19, IIMA , IIMB, XLRI
WE: Information Technology (Consulting)
GMAT ToolKit User CAT Tests
If the circle above has center O and circumference 18m, then the perim [#permalink]

Show Tags

New post 21 May 2017, 18:06
carcass wrote:
Image

If the circle above has center O and circumference 18π, then the perimeter of sector RSTO Is

(A) 3π + 9

(B) 3π + 18

(C) 6π + 9

(D) 6π + 18

(E) 6π + 24


[Reveal] Spoiler:
Attachment:
6p5jvHu.jpg


Circumference = 2\(\pi\)r = 18\(\pi\)
r = \(\frac{18}{2}\) = 9

Perimeter of sector RSTO = Arc Length + r + r
Arc Length = 2\(\pi\)r\(\frac{C}{360}\) (C is central angle of the sector)
C = \(60^{\circ}\)
Arc Length = 2\(\pi\)r\(\frac{60}{360}\) = 2*9*\(\pi\)\(\frac{60}{360}\) = 3\(\pi\)

Therefore Perimeter of sector RSTO = 3\(\pi\) + 9 + 9 = 3\(\pi\) + 18
Answer B...

_________________
Kindly press "+1 Kudos" to appreciate :)
Intern
Intern
avatar
B
Joined: 28 May 2015
Posts: 29
Location: India
Schools: HEC Dec '17
GMAT 1: 710 Q51 V34
GPA: 2.2
Reviews Badge
Re: If the circle above has center O and circumference 18m, then the perim [#permalink]

Show Tags

New post 22 May 2017, 12:20
Let's solve it part by part

Arc makes 60 deg i.e. 1/6 of 360 deg that is 1/6 of circumference = π.18/6 = 3.π

Now we know the formula of circumference = π . D where D is diameter
C = π• 18
Observe OR + OT = diameter = 18

Answer B

Sent from my Redmi Note 3 using GMAT Club Forum mobile app
Re: If the circle above has center O and circumference 18m, then the perim   [#permalink] 22 May 2017, 12:20
Display posts from previous: Sort by

If the circle above has center O and circumference 18m, then the perim

  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®.