Find all School-related info fast with the new School-Specific MBA Forum

It is currently 31 Aug 2014, 00:49

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Helga and Rob like corn on cob. Each prefers to eat the gene

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Director
Director
User avatar
Joined: 22 Mar 2011
Posts: 613
WE: Science (Education)
Followers: 68

Kudos [?]: 505 [1] , given: 43

GMAT Tests User
Helga and Rob like corn on cob. Each prefers to eat the gene [#permalink] New post 06 Aug 2012, 04:46
1
This post received
KUDOS
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

32% (02:41) correct 68% (00:35) wrong based on 19 sessions
Helga and Rob like corn on the cob. Each prefers to eat the genetically modified type corn, which has perfect cylindrical shape.
Helga likes to eat her corn by chewing circular strips of equal width. Rob prefers to go along the height of the cylinder, munching straight strips of the same width as Helga's strips. If Helga eats half as many circular strips as Rob eats straight strips, what is the ratio between the height and the radius of the corn on the cob?

(A)\, 1:2
(B)\, 2:1
(C)\, 1:\pi
(D)\, \pi:1
(E)\, 1:\sqrt{\pi}
[Reveal] Spoiler: OA

_________________

PhD in Applied Mathematics
Love GMAT Quant questions and running.

Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 25207
Followers: 3422

Kudos [?]: 25126 [1] , given: 2702

Re: Helga and Rob like corn on cob. Each prefers to eat the gene [#permalink] New post 06 Aug 2012, 05:04
1
This post received
KUDOS
Expert's post
EvaJager wrote:
Helga and Rob like corn on cob. Each prefers to eat the genetically modified type corn, which has perfect cylindrical shape.
Helga likes to eat her corn by chewing circular strips of equal width. Rob prefers to go along the height of the cylinder, munching straight strips of the same width as Helga's strips. If Helga eats half as many circular strips as Rob eats straight strips, what is the ratio between the height and the radius of the corn on cob?

(A)\, 1:2
(B)\, 2:1
(C)\, 1:\pi
(D)\, \pi:1
(E)\, 1:\sqrt{\pi}


Say the the width of the strip each eats is x.

Since Helga eats the corn circularly, then the number of strips she eats is \frac{h}{x}.
Since Rob eats the corn along the height, then the number of strips he eats is \frac{2\pi{r}}{x}.

We are told that \frac{h}{x}=\frac{1}{2}*\frac{2\pi{r}}{x} --> \frac{h}{r}=\pi.

Answer: D.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 22 Feb 2010
Posts: 49
Followers: 0

Kudos [?]: 6 [0], given: 1

GMAT ToolKit User
Re: Helga and Rob like corn on cob. Each prefers to eat the gene [#permalink] New post 17 Aug 2012, 19:55
Bunuel wrote:
EvaJager wrote:
Helga and Rob like corn on cob. Each prefers to eat the genetically modified type corn, which has perfect cylindrical shape.
Helga likes to eat her corn by chewing circular strips of equal width. Rob prefers to go along the height of the cylinder, munching straight strips of the same width as Helga's strips. If Helga eats half as many circular strips as Rob eats straight strips, what is the ratio between the height and the radius of the corn on cob?

(A)\, 1:2
(B)\, 2:1
(C)\, 1:\pi
(D)\, \pi:1
(E)\, 1:\sqrt{\pi}


Say the the width of the strip each eats is x.

Since Helga eats the corn circularly, then the number of strips she eats is \frac{h}{x}.
Since Rob eats the corn along the height, then the number of strips he eats is \frac{2\pi{r}}{x}.

We are told that \frac{h}{x}=\frac{1}{2}*\frac{2\pi{r}}{x} --> \frac{h}{r}=\pi.

Answer: D.


Please explain how you obtained the number of strips eaten by each of them; how was the equality obtained? How can we use the information about the way of their eating corn to determine the number of strips eaten by each of them.
Senior Manager
Senior Manager
User avatar
Joined: 19 Apr 2011
Posts: 291
Schools: Booth,NUS,St.Gallon
Followers: 4

Kudos [?]: 73 [0], given: 51

GMAT Tests User
Re: Helga and Rob like corn on cob. Each prefers to eat the gene [#permalink] New post 20 Aug 2012, 09:51
The circumference of the cylinder is 2*pi*r.
Dividing by x gives the number of vertical strips ,because each strip is of width x.
The height of the cylinder is h.Dividing by x will give you the number of horizontal strips.
Now apply the data given in the question and equate.
Hope this helps .
_________________

+1 if you like my explanation .Thanks :)

Re: Helga and Rob like corn on cob. Each prefers to eat the gene   [#permalink] 20 Aug 2012, 09:51
    Similar topics Author Replies Last post
Similar
Topics:
Of a group of people, 10 like to eat peanuts, 11 like to eat joemama142000 7 20 Feb 2006, 17:05
Like other educators who prefer to substitute anthologies of nakib77 4 15 Dec 2005, 08:26
Like other educators who prefer to substitute anthologies of sgrover 8 18 Sep 2005, 20:30
Like other educators who prefer to substitute anthologies of AJB77 3 06 Aug 2005, 07:19
Like other educators who prefer to substitute anthologies of nocilis 8 21 Dec 2004, 00:54
Display posts from previous: Sort by

Helga and Rob like corn on cob. Each prefers to eat the gene

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.