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

It is currently 20 Aug 2014, 06:52

Starting Soon:

Live Q&A Session with Cambridge Admissions Team   ||    Join Chat Room to Attend the Session


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

A company has two models of computers, model M and model N

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Manager
Manager
User avatar
Joined: 28 May 2009
Posts: 155
Followers: 4

Kudos [?]: 85 [1] , given: 89

GMAT ToolKit User
A company has two models of computers, model M and model N [#permalink] New post 05 Feb 2013, 16:04
1
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

74% (02:01) correct 26% (01:31) wrong based on 90 sessions
A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12

Source: Gmat Hacks 1800
[Reveal] Spoiler: OA

_________________

New to GMAT Club? Start here

Kindle Flashcards - Quant (Official Gmat Club, miguemick's Quant topics), and Verbal (Official Gmat Club) - in Kindle (azw3) format

Kaplan Promo CodeKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
Expert Post
3 KUDOS received
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 4665
Location: Pune, India
Followers: 1070

Kudos [?]: 4771 [3] , given: 163

Re: A company has two models of computers, model M and model N [#permalink] New post 05 Feb 2013, 20:29
3
This post received
KUDOS
Expert's post
megafan wrote:
A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12


Source: Gmat Hacks 1800


Time taken by model M computer to complete 1 work = 18 mins so Rate of work of model M = 1/18 work/min
Time taken by model N computer to complete 1 work = 9 mins so Rate of work of model N = 1/9 work/min

1 work was completed in 1 min so combined rate of work of x computers of M type and x computers of N type = 1 work/min
(because Work = Rate*Time)

x/18 + x/9 = 1 (Rates are additive)
x = 6

Answer (C)

There are only two things to remember in work rate questions:
1. Rates are Additive.
2. Work = Rate*Time
(which implies Rate = 1/Time)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Save $100 on Veritas Prep GMAT Courses And Admissions Consulting
Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.

Veritas Prep Reviews

Moderator
Moderator
User avatar
Joined: 02 Jul 2012
Posts: 1226
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 65

Kudos [?]: 655 [0], given: 116

GMAT Tests User Premium Member
Re: A company has two models of computers, model M and model N [#permalink] New post 05 Feb 2013, 21:43
megafan wrote:
A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12


Source: Gmat Hacks 1800


Let's say 1 work is processing 18 gb of data.

Model M : 1 gb per min

Model N : 2 gb per min

Working together, 1 M and 1 N = 3 gb per min

So, 6 times as many computers would work at 18 gb per min.

So no. of M = 6

Answer is C
_________________

Did you find this post helpful?... Please let me know through the Kudos button.

Thanks To The Almighty - My GMAT Debrief

GMAT Reading Comprehension: 7 Most Common Passage Types

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 19027
Followers: 3361

Kudos [?]: 24360 [0], given: 2677

Re: A company has two models of computers, model M and model N [#permalink] New post 05 Feb 2013, 23:56
Expert's post
megafan wrote:
A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12

Source: Gmat Hacks 1800


Another copied question from Gmat hacks. Original question from GMAT Prep:

Quote:
A company has two types of machines, type R and type S. Operating at a constant rate, a machine of type R does a certain job in 36 hrs and a machine of type S does the same job in 18 hours. If the company used the same number of each type of machine to do the job in 2 hours, how many machines of type R were used?

A. 3
B. 4
C. 6
D. 9
E. 12


Discussed here: a-company-has-two-types-of-machines-type-r-and-type-s-130108.html
_________________

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

Manager
Manager
avatar
Joined: 14 Mar 2013
Posts: 51
Location: United States
Concentration: General Management, Leadership
GMAT Date: 12-03-2013
WE: General Management (Retail)
Followers: 0

Kudos [?]: 17 [0], given: 119

Re: A company has two models of computers, model M and model N [#permalink] New post 23 Nov 2013, 04:19
M = 1 job in 18 min → 1/18
N = 1 job in 09 min → 1/9

M+N = 1/18 + 1/9 = 3/18 = 1/6

M+N = 1 job in 6 minutes.

To complete the job in 1 min will be necessary 6 M+N.

Ans C

-------------
Please +KUDOS if you like my answer. :-D
Re: A company has two models of computers, model M and model N   [#permalink] 23 Nov 2013, 04:19
    Similar topics Author Replies Last post
Similar
Topics:
2 A toy company's engineering department developed a new model wastedyouth 4 09 Dec 2013, 10:44
2 Experts publish their posts in the topic A new computer program for 3-D modeling akashb106 2 19 Sep 2013, 21:31
8 Experts publish their posts in the topic A certain research group plans to create computer models of suyash23n 13 09 Sep 2013, 09:59
Business Models Praetorian 3 19 Jul 2006, 01:07
If the regulation of computer networks is to be modeled on Antmavel 6 08 Nov 2005, 18:58
Display posts from previous: Sort by

A company has two models of computers, model M and model N

  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®.