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

 It is currently 27 Aug 2016, 03:50

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

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

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

### Hide Tags

Manager
Joined: 28 May 2009
Posts: 155
Location: United States
Concentration: Strategy, General Management
GMAT Date: 03-22-2013
GPA: 3.57
WE: Information Technology (Consulting)
Followers: 7

Kudos [?]: 175 [1] , given: 91

A company has two models of computers, model M and model N [#permalink]

### Show Tags

05 Feb 2013, 17:04
1
This post received
KUDOS
00:00

Difficulty:

25% (medium)

Question Stats:

74% (02:04) correct 26% (01:26) wrong based on 126 sessions

### HideShow timer Statistics

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

_________________
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 6830
Location: Pune, India
Followers: 1926

Kudos [?]: 11947 [3] , given: 221

Re: A company has two models of computers, model M and model N [#permalink]

### Show Tags

05 Feb 2013, 21:29
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

Get started with Veritas Prep GMAT On Demand for \$199

Veritas Prep Reviews

Moderator
Joined: 02 Jul 2012
Posts: 1230
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 110

Kudos [?]: 1254 [0], given: 116

Re: A company has two models of computers, model M and model N [#permalink]

### Show Tags

05 Feb 2013, 22:43
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

Math Expert
Joined: 02 Sep 2009
Posts: 34453
Followers: 6275

Kudos [?]: 79614 [0], given: 10022

Re: A company has two models of computers, model M and model N [#permalink]

### Show Tags

06 Feb 2013, 00:56
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
_________________
Intern
Joined: 14 Mar 2013
Posts: 48
Location: United States
Concentration: General Management, Leadership
GMAT Date: 12-03-2013
WE: General Management (Retail)
Followers: 0

Kudos [?]: 48 [0], given: 119

Re: A company has two models of computers, model M and model N [#permalink]

### Show Tags

23 Nov 2013, 05:19
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.
Re: A company has two models of computers, model M and model N   [#permalink] 23 Nov 2013, 05:19
Similar topics Replies Last post
Similar
Topics:
A certain automobile company’s best-selling model is the Speedster. Th 1 28 Feb 2016, 09:43
A television manufacturer produces 600 units of a certain model each m 1 21 Dec 2015, 20:53
5 A computer company prices its models using the formula P = {1.25^s}a, 6 04 May 2015, 06:06
22 A certain research group plans to create computer models of 18 09 Sep 2013, 10:59
48 Out of seven models, all of different heights, five models 19 27 Oct 2007, 12:34
Display posts from previous: Sort by

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

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

 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®.