Machine rate problem : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 20 Jan 2017, 06:27

### 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

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

# Machine rate problem

Author Message
TAGS:

### Hide Tags

Intern
Joined: 07 Jun 2011
Posts: 2
Followers: 0

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

### Show Tags

07 Jun 2011, 13:00
00:00

Difficulty:

(N/A)

Question Stats:

100% (03:32) correct 0% (00:00) wrong based on 1 sessions

### HideShow timer Statistics

Hi All,

Machine A @ constant rate 9,000/H
Machine B @ Constant rate 7,000/H

If both together, then it can produces 100,000 in 8 hours, then what is the minumum hours is needed for machine B to run?

The answer was at least 4 hours.

This is the equation I think is correct: 9000/A + 7000/B = 10000/8. However, I don't know how to get another equation since i have 2 unknowns.

Thanks!
CEO
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 548

Kudos [?]: 3559 [0], given: 360

### Show Tags

07 Jun 2011, 15:17
It seems that something is wrong with your question.

A&B together have 16,000/h rate and over 8h it will be 128,000 (not 100,000). Or am I missing something?
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Manager
Joined: 28 Feb 2011
Posts: 90
Followers: 0

Kudos [?]: 41 [1] , given: 2

### Show Tags

07 Jun 2011, 17:27
1
KUDOS
We have to find out the minumum no. hours that machine B HAS to run. Now we have the output for 8 hrs for both the machines (nothing given about the no. of hrs each runs)

Lets assume Machine A runs for full 8 hrs..it produces 72000 units.
Now the remaining 28000 have to be produced by B..which it would do in 28000/7000 = 4 hrs...

I would slightly tweak the wording in the problem to say "if both of them operate simultenously or otherwise for 8 hrs..." (but I guess it would make the question far to easy!!)
_________________

Fight till you succeed like a gladiator..or doom your life which can be invincible

Manager
Joined: 16 Mar 2011
Posts: 177
Followers: 1

Kudos [?]: 37 [0], given: 13

### Show Tags

08 Jun 2011, 00:51
So you're saying B HAS to run for atleast 4 hours? But what if A runs less than 8 hrs.. Is it given that it has to run for atleast 7 hours? I think than the answer would change unless the result has to be an integer multiple of both rates.. I was actually thinking the same thing as walker about the combined rate.. Anyone?
Manager
Joined: 28 Feb 2011
Posts: 90
Followers: 0

Kudos [?]: 41 [1] , given: 2

### Show Tags

08 Jun 2011, 01:26
1
KUDOS
l0rrie wrote:
So you're saying B HAS to run for atleast 4 hours? But what if A runs less than 8 hrs.. Is it given that it has to run for atleast 7 hours? I think than the answer would change unless the result has to be an integer multiple of both rates.. I was actually thinking the same thing as walker about the combined rate.. Anyone?
The question asks the min. no of hrs B should run..we have a given output and no. Of hrs..A can run for a maximum of 8 hrs..and the shortfall in the output would be covered by B..
I agree the language of the question can be improved but this is what I think given the problem at hand...

Posted from my mobile device
_________________

Fight till you succeed like a gladiator..or doom your life which can be invincible

Intern
Joined: 07 Jun 2011
Posts: 2
Followers: 0

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

### Show Tags

08 Jun 2011, 08:59
I think maverick04 is correct. I see how you solved the problem now. Thanks so much. Sorry for wording the question so badly. I got it off this online problem generating website and I am unable to regenerator the same problem. I wrote down the problem in short-hand style and so I don't remember the exact wording. Again, Thanks so much for all your help.
Manager
Joined: 28 Feb 2011
Posts: 90
Followers: 0

Kudos [?]: 41 [1] , given: 2

### Show Tags

08 Jun 2011, 17:15
1
KUDOS
teebumble wrote:
I think maverick04 is correct. I see how you solved the problem now. Thanks so much. Sorry for wording the question so badly. I got it off this online problem generating website and I am unable to regenerator the same problem. I wrote down the problem in short-hand style and so I don't remember the exact wording. Again, Thanks so much for all your help.

Anytime mate
_________________

Fight till you succeed like a gladiator..or doom your life which can be invincible

Manager
Joined: 08 Sep 2010
Posts: 166
Followers: 0

Kudos [?]: 23 [0], given: 18

### Show Tags

10 Jun 2011, 20:40
16,000*x + 9000(8-x) = 1,00,000

so x will be 4 hrs
_________________

My will shall shape the future. Whether I fail or succeed shall be no man's doing but my own.

If you like my explanations award kudos.

Senior Manager
Status: mba here i come!
Joined: 07 Aug 2011
Posts: 270
Followers: 42

Kudos [?]: 1058 [0], given: 48

### Show Tags

11 Aug 2011, 05:20
A+B in 1 hr produce 9+7 = 16k
in 8hrs = 128k

but we need only 100k in 8hrs. so we have 28k extra. let's give B some rest.

128k/7k = 4hrs

so B will rest for 4 hours and, thus, will work for 4 hrs (8-4)
_________________

press +1 Kudos to appreciate posts

VP
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 1353
Followers: 17

Kudos [?]: 240 [0], given: 10

### Show Tags

11 Aug 2011, 23:25
100- 9*8 = 28

thus 7*4 hrs = 28

hence 4
_________________

Visit -- http://www.sustainable-sphere.com/
Promote Green Business,Sustainable Living and Green Earth !!

Re: Machine rate problem   [#permalink] 11 Aug 2011, 23:25
Similar topics Replies Last post
Similar
Topics:
1 Machine A can do a job in 12 hours at a constant rate and machine A do 3 03 Nov 2016, 00:28
1 Machine A can do a job in 24 hours at a constant rate and machine A do 5 11 Mar 2016, 05:04
15 Machine A and machine B process the same work at different rates. Mac 9 12 Mar 2015, 05:44
147 Running at their respective constant rates, machine X takes 42 05 Aug 2010, 01:01
15 Six machines, each working at the same constant rate 18 26 Apr 2010, 20:53
Display posts from previous: Sort by

# Machine rate problem

 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®.