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

It is currently 23 Oct 2018, 05:10

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

If 16 machine can finish a job in 36 days, then how many more machines

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

Hide Tags

Manager
Manager
User avatar
P
Joined: 13 Jun 2012
Posts: 191
Location: United States
WE: Supply Chain Management (Computer Hardware)
GMAT ToolKit User CAT Tests
If 16 machine can finish a job in 36 days, then how many more machines  [#permalink]

Show Tags

New post 10 May 2015, 12:04
6
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

72% (01:56) correct 28% (02:23) wrong based on 132 sessions

HideShow timer Statistics

If 16 machine can finish a job in 36 days, then how many more machines would be needed to finish the job in one -third less time?

a. 4
b. 8
c. 10
d. 12
e. 16
GMAT Tutor
avatar
S
Joined: 24 Jun 2008
Posts: 1327
Re: If 16 machine can finish a job in 36 days, then how many more machines  [#permalink]

Show Tags

New post 10 May 2015, 13:13
1
2
You might think of this in a management context - we can use the principle of 'person-hours' to solve any problem where we have identical workers. So, using simpler numbers, suppose you know that 6 identical employees, working simultaneously, would finish a job in 5 hours. Then that job requires 6*5 = 30 total hours of person-work. If instead you wanted the job done in 3 hours, you'd assign 30/3 = 10 employees to do the job, because you want to get a total of 30 hours of work from the employees.

We can solve this problem identically. If 16 machines (identical ones, I assume) work simultaneously for 36 days, they will do a total of 16*36 machine-days of work. So the job requires 16*36 days of machine work in total. We instead want the job done in 1/3 less time, so in 24 days. So we'll need 16*36/24 = 24 machines, or 8 additional machines.
_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

Manager
Manager
avatar
B
Joined: 12 Nov 2014
Posts: 63
CAT Tests
Re: If 16 machine can finish a job in 36 days, then how many more machines  [#permalink]

Show Tags

New post 10 May 2015, 20:28
2
Hi,

16 machines can finish a JOB in 36 days.
Let me re frame the sentence here:

In 36 days 16 machines can finish a JOB.
In 1 day 16 machines can finish (1/36) part of JOB
In 1 day 1 machine can finish 1/(36*16) part of JOB---------------------------- (1)

We know that the JOB has to be completed in one-third less time which means 36-1/3*(36) = 24 days

From (1)
In 24 days 1 machine can finish 24/(36*16) part of JOB i.e. 1/24 part of JOB
So you need 24 machines to finish the JOB in 24 days.

So number of extra machines that you need is 24 -16 = 8

Answer B

Hope the explanation is clear!
Consider giving Kudos


Ambarish
_________________

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kindly press Kudos if the explanation is clear.
Thank you
Ambarish

Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8417
Location: Pune, India
Re: If 16 machine can finish a job in 36 days, then how many more machines  [#permalink]

Show Tags

New post 10 May 2015, 22:12
2
Turkish wrote:
If 16 machine can finish a job in 36 days, then how many more machines would be needed to finish the job in one -third less time?

a. 4
b. 8
c. 10
d. 12
e. 16


Use "Work-Rate using Joint Variation" approach discussed here: http://www.veritasprep.com/blog/2013/02 ... variation/

36 days - 16 machines
24 days (1/3rd less time) - ?? machines

Since the number of machines required will increase, you will multiply 16 by 36/24 (greater than 1).
New number of machines = 16 * (36/24) = 24

So you need 8 extra machines
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 8541
Premium Member
Re: If 16 machine can finish a job in 36 days, then how many more machines  [#permalink]

Show Tags

New post 27 Jul 2018, 10:49
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

GMAT Club Bot
Re: If 16 machine can finish a job in 36 days, then how many more machines &nbs [#permalink] 27 Jul 2018, 10:49
Display posts from previous: Sort by

If 16 machine can finish a job in 36 days, then how many more machines

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


Copyright

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®.