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

 It is currently 06 May 2015, 05:41

### 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

# Six machines, each working at the same constant rate,

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Manager
Joined: 30 Jan 2006
Posts: 146
Followers: 1

Kudos [?]: 9 [0], given: 0

Six machines, each working at the same constant rate, [#permalink]  06 Apr 2006, 14:24
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Six machines, each working at the same constant rate, together can complete a certain job in 12 days. How many additional machines, each working at the same constant rate, will be needed to complete the job in 8 days?

This one is easy to solve, but I'm interested in finding out in how many different ways people can solve this. Please explain your answers.
Manager
Joined: 09 Feb 2006
Posts: 129
Location: New York, NY
Followers: 1

Kudos [?]: 3 [0], given: 0

[#permalink]  06 Apr 2006, 14:36
Well there is the easy way.

w=rt
1 = r12
1/12 = r

Each machine has a rate of 1/72.

To determine how many machines we need, let x be the number of machines.

1 = (x/72)*8
1 = x/9

x = 9

You need 9 machines to complete the job is 8 days.
Manager
Joined: 30 Jan 2006
Posts: 146
Followers: 1

Kudos [?]: 9 [0], given: 0

[#permalink]  06 Apr 2006, 16:07
Thanks guys
Intern
Joined: 02 Feb 2006
Posts: 1
Followers: 0

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

[#permalink]  06 Apr 2006, 22:05
Doesn't the question ask for the number of ADDITONAL machines necessary to complete the job in 8 days?
Manager
Joined: 21 Dec 2005
Posts: 103
Followers: 1

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

[#permalink]  07 Apr 2006, 23:14
anbu wrote:
Doesn't the question ask for the number of ADDITONAL machines necessary to complete the job in 8 days?

You are right,,I agree with you. So answer is 3 machines.
Intern
Joined: 18 Apr 2006
Posts: 5
Followers: 0

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

[#permalink]  05 May 2006, 07:14
GMAT trap
VP
Joined: 08 Jun 2005
Posts: 1147
Followers: 6

Kudos [?]: 128 [0], given: 0

[#permalink]  05 May 2006, 11:33
I have a different approach.
If 6 machines do the work in 12 days,
to do the same work in 8 days you have to work 1.5 times as hard
meaning 6 x 1.5 = 9 machines

So the answer is 9 - 6 = 3
Manager
Joined: 27 Jan 2006
Posts: 156
Location: Europe
Followers: 1

Kudos [?]: 2 [0], given: 0

[#permalink]  05 May 2006, 13:39
easy tips

6*12=X*8

X=9

so 3 more machine needed
Intern
Joined: 14 Jan 2006
Posts: 20
Location: Visakhapatnam, India
Followers: 0

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

[#permalink]  05 May 2006, 19:47
Machines : Days : Work
6 : 12 : 1 (6 machines complete in 12 days 1 work)
? : 8 : 1 (How many machines complete in 8 days 1 work)

? = 12*6/8 = 9
Therefore, 3 more machines required.[/list]
Manager
Joined: 27 Mar 2006
Posts: 136
Followers: 1

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

[#permalink]  07 May 2006, 12:20
Agree with 3
Senior Manager
Joined: 29 Jun 2005
Posts: 403
Followers: 1

Kudos [?]: 15 [0], given: 0

[#permalink]  08 May 2006, 08:39
Agree with 3.
One machine can complete a job in 72 days - 72*1/6=12. 72*1/x=8  x=9. So, 9-6=3. Three additional machines are needed.
[#permalink] 08 May 2006, 08:39
Similar topics Replies Last post
Similar
Topics:
10 Six machines, each working at the same constant rate 17 26 Apr 2010, 20:53
Six machines, each working at the same constant rate, 1 09 Feb 2007, 20:43
Six machines, each working at the same constant rate, 4 19 Nov 2006, 22:09
Six machines, each working at the same constant rate, 6 21 Oct 2006, 09:45
Six machines, each working at the same constant rate, 3 21 May 2006, 13:51
Display posts from previous: Sort by

# Six machines, each working at the same constant rate,

 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®.