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

It is currently 20 Sep 2018, 15:33

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 operation above rotates the regular pentagon clockwise by (72n) de

  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: 49271
The operation above rotates the regular pentagon clockwise by (72n) de  [#permalink]

Show Tags

New post 08 Jul 2015, 03:53
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

60% (01:06) correct 40% (01:24) wrong based on 83 sessions

HideShow timer Statistics

Image
The operation above rotates the regular pentagon clockwise by (72n) degrees from its center. What replaces the initial b position when n = 4?

A. a
B. b
C. c
D. d
E. e

Kudos for a correct solution.

Attachment:
pentagon.gif
pentagon.gif [ 1.85 KiB | Viewed 1623 times ]

_________________

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

SVP
SVP
User avatar
P
Joined: 08 Jul 2010
Posts: 2314
Location: India
GMAT: INSIGHT
WE: Education (Education)
Reviews Badge
Re: The operation above rotates the regular pentagon clockwise by (72n) de  [#permalink]

Show Tags

New post 08 Jul 2015, 04:20
2
Bunuel wrote:
Image
The operation above rotates the regular pentagon clockwise by (72n) degrees from its center. What replaces the initial b position when n = 4?

A. a
B. b
C. c
D. d
E. e

Kudos for a correct solution.

Attachment:
pentagon.gif


The central Angle will be divided in to 5 equal parts when all vertices are joined with the centre of the Pentagon

Therefore Each angle = 360/5 = 72 Degree

i.e. When the Pentagon Rotates by 72 degrees then A replaced the Point B
i.e. When the Pentagon Rotates by 72*2 degrees then E replaced the Point B
i.e. When the Pentagon Rotates by 72*3 degrees then D replaced the Point B
i.e. When the Pentagon Rotates by 72*4 degrees then C replaced the Point B

Answer: Option C
_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49271
Re: The operation above rotates the regular pentagon clockwise by (72n) de  [#permalink]

Show Tags

New post 13 Jul 2015, 02:21
Bunuel wrote:
Image
The operation above rotates the regular pentagon clockwise by (72n) degrees from its center. What replaces the initial b position when n = 4?

A. a
B. b
C. c
D. d
E. e

Kudos for a correct solution.

Attachment:
pentagon.gif


800score Official Solution:

Think of the polygon as you would a wheel being rotated at its center. A wheel sweeps a 360º angle everytime it returns to its initial positon. Since this is a regular pentagon, we can increment our rotations by dividing 360/5 = 72.

So everytime the center spins 72º clockwise, the polygon moves by one vertex. So, when n = 4 the pentagon rotates by 4 vertices and the initial b position is replaced by c or answer choice (C).

An alternative way to consider the problem is to realize that everytime n = 5, it returns to its original configuration. So, when n = 4, the position is occupied by the vertex that is one vertex away in the clockwise direction because it lags by one 72º turn.
_________________

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

Senior Manager
Senior Manager
User avatar
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 421
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Re: The operation above rotates the regular pentagon clockwise by (72n) de  [#permalink]

Show Tags

New post 14 Jul 2015, 05:24
Since 360/5 = 72, and the equation rotates the corners by 72 degrees, then for 4*72 each number will be moved 4 corners ahead.

So, b will go to a and c will go to b.
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 8104
Premium Member
Re: The operation above rotates the regular pentagon clockwise by (72n) de  [#permalink]

Show Tags

New post 23 Aug 2018, 00:21
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: The operation above rotates the regular pentagon clockwise by (72n) de &nbs [#permalink] 23 Aug 2018, 00:21
Display posts from previous: Sort by

The operation above rotates the regular pentagon clockwise by (72n) de

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

Events & Promotions

PREV
NEXT


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®.