It is currently 27 Jun 2017, 07:47

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Working alone, printers X, Y, and Z can do a certain

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

Hide Tags

3 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 12 Mar 2006
Posts: 365
Schools: Kellogg School of Management
Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 27 Jan 2007, 16:12
3
This post received
KUDOS
7
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

64% (02:26) correct 36% (01:25) wrong based on 443 sessions

HideShow timer Statistics

Working alone, printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 15, and 18 hours, respectively. What is the ratio of the time it takes printer X to do the job, working alone at its rate, to the time it takes printers Y and Z to do the job, working together at their individual rates ?

(A) 4/11
(B) 1/2
(C) 15/22
(D) 22/15
(E) 11/4
[Reveal] Spoiler: OA
1 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 19 Jul 2006
Posts: 358
 [#permalink]

Show Tags

New post 27 Jan 2007, 18:39
1
This post received
KUDOS
D

X takes 12 hrs

Y and Z together = (1/15) + (1/18) = 11/90 = 90/11 hrs

ratio = X /( YandZ) = 12 * (11/90) = 22/15
Manager
Manager
avatar
Joined: 10 Dec 2005
Posts: 112
 [#permalink]

Show Tags

New post 01 Feb 2007, 22:23
Indeed D is the correct answer, got 22/15 by the exact same approach
_________________

"Live as if you were to die tomorrow. Learn as if you were to live forever." - Mahatma Gandhi

1 KUDOS received
Senior Manager
Senior Manager
User avatar
Joined: 04 Jan 2006
Posts: 279
 [#permalink]

Show Tags

New post 02 Feb 2007, 15:53
1
This post received
KUDOS
Rate(X) = 1/12 job/hour or 12 hour/job
Rate(Y) = 1/15 job/hour
Rate(Z) = 1/18 job/hour

Rate(Y + Z) = 1/15 + 1/18 job/hour = (6 + 5)/90 = 11/90 job/hour

This mean that Machine Y and Z can finish 11/90 job in one hour

So how long will will take for Machine X to finish 11/90 job? Rate(X) = 12 hour/job
Time(x) to do 11/90 job = 11/90 job x 12 hour/job = 11 x 12 /90 = 44/30 = 22/15 hours

(D) is the answer.
1 KUDOS received
Intern
Intern
avatar
Joined: 17 Dec 2012
Posts: 9
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 23 Jan 2013, 13:12
1
This post received
KUDOS
Hi,

if somebody could help me what I am doing wrong here, it would be great:

1) I am calculating individual rates for all 3 printer and bring them onto the same denominator.
X = 1/12 = 30/360
Y = 1/15 = 24/360
Z = 1/18 = 20/360

2) Comparing the nominators of X with the sum of Y and Z, since they are now comparable.
30/(24+20) = 30/44 = 15/22

The ratio is X to (Y + Z) so it should be fine.
This would be answer (C) and not (D).
Why should I flip the nominator and denominator here? :?:

Thanks for your help in advance
Expert Post
5 KUDOS received
Veritas Prep GMAT Instructor
User avatar
S
Joined: 16 Oct 2010
Posts: 7446
Location: Pune, India
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 23 Jan 2013, 20:02
5
This post received
KUDOS
Expert's post
leventg wrote:
Hi,

if somebody could help me what I am doing wrong here, it would be great:

1) I am calculating individual rates for all 3 printer and bring them onto the same denominator.
X = 1/12 = 30/360
Y = 1/15 = 24/360
Z = 1/18 = 20/360

2) Comparing the nominators of X with the sum of Y and Z, since they are now comparable.
30/(24+20) = 30/44 = 15/22

The ratio is X to (Y + Z) so it should be fine.
This would be answer (C) and not (D).
Why should I flip the nominator and denominator here? :?:

Thanks for your help in advance


RATES of X, Y and Z are 30/360, 24/360 and 20/360

Ratio of RATE of X:RATE of Y+Z = 30:44 = 15:22

The question asks for the ratio of TIME TAKEN = 1/15 : 1/22 = 22:15
(Time taken is the inverse of rate)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Intern
Intern
avatar
Joined: 17 Dec 2012
Posts: 9
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 24 Jan 2013, 04:23
Thanks for your fast reply Karishma, :-D

As this was still difficult for me to understand, I have created an easy example for better understanding.
Let’s assume all printers take 12 hours. So printer Y and Z are doing the same job as printer X twice as fast.

X = 1/12 (job/hours)
Y = 1/12 (job/hours)
Z = 1/12 (job/hours)
Y+Z = 2/12 = 1/6 (job/hours)

X : (Y+Z) = 1 : 2 => This ratio refers to the output.

Regarding Time Taken, X makes in 12 hours 1 job and Y+Z are doing in 6 hours 1 job.
So what you are saying is that we are comparing the hours and not the jobs right?
And therefore the ratio of X : Y is 12 : 6, which is 2 : 1.

Summarizing both steps:
X : (Y+Z) = (1/12) : (2/12) = 1 : 2 => This ratio refers to the output.
X : (Y+Z) = (1/12) : (1/6) = 12: 6 = 2 : 1 => This ratio refers to the time

Referring to my example again:
X = 12 hours
Y+Z = 6 hours
Ratio is not 12 : 6 or 2 : 1 because time taken is inverse to rate?
Instead the Ratio is (1/12) : (1/6) = (6/12) = 1 : 2

Actually this TIME-IS-INVERSE-APPROACH is quite difficult to understand. I can apply it but still it is difficult to understand. May be it is just easier to divide 2 fractions. (Divide Y+Z by X).

Last edited by leventg on 24 Jan 2013, 06:04, edited 1 time in total.
Expert Post
1 KUDOS received
Veritas Prep GMAT Instructor
User avatar
S
Joined: 16 Oct 2010
Posts: 7446
Location: Pune, India
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 24 Jan 2013, 04:40
1
This post received
KUDOS
Expert's post
leventg wrote:
Thanks for your fast reply Karishma, :-D

As this was still difficult for me to understand, I have created an easy example for better understanding.
Let’s assume all printers take 12 hours. So printer Y and Z are doing the same job as printer X twice as fast.

X = 1/12 (job/hours)
Y = 1/12 (job/hours)
Z = 1/12 (job/hours)
Y+Z = 2/12 = 1/6 (job/hours)

X : (Y+Z) = 1 : 2 => This ratio refers to the output.

Regarding Time Taken, X makes in 12 hours 1 job and Y+Z are doing in 6 hours 1 job.
So what you are saying is that we are comparing the hours and not the jobs right?
And therefore the ratio of X : Y is 12 : 6, which is 2 : 1.

Summarizing both steps:
X : (Y+Z) = (1/12) : (2/12) = 1 : 2 => This ratio refers to the output.
X : (Y+Z) = (1/12) : (1/6) = 2 : 1 => This ratio refers to the time.


Referring to my example again:
X = 12 hours
Y+Z = 6 hours
Ratio is not 12 : 6 or 2 : 1 because time taken is inverse to rate?
Instead the Ratio is (1/12) : (1/6) = (6/12) = 1 : 2

Actually this TIME-IS-INVERSE-APPROACH is quite difficult to understand. I can apply it but still it is difficult to understand. May be it is just easier to divide 2 fractions. (Divide Y+Z by X).


For an intuitive understanding of ratios approach, check out these posts:
http://www.veritasprep.com/blog/2011/03 ... of-ratios/
http://www.veritasprep.com/blog/2011/03 ... os-in-tsd/
http://www.veritasprep.com/blog/2011/03 ... -problems/
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 16002
Premium Member
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 19 Jan 2015, 13:29
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

Senior Manager
Senior Manager
User avatar
B
Status: Professional GMAT Tutor
Affiliations: AB, cum laude, Harvard University (Class of '02)
Joined: 10 Jul 2015
Posts: 367
Location: United States (CA)
GMAT 1: 770 Q47 V48
GMAT 2: 730 Q44 V47
GRE 1: 337 Q168 V169
WE: Education (Education)
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 05 May 2016, 18:17
Attached is a visual that should help.
Attachments

Screen Shot 2016-05-05 at 6.16.09 PM.png
Screen Shot 2016-05-05 at 6.16.09 PM.png [ 100.35 KiB | Viewed 3992 times ]


_________________

Harvard grad and 770 GMAT scorer, offering high-quality private GMAT tutoring, both in-person and via Skype, since 2002.

McElroy Tutoring

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 16002
Premium Member
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 08 Jun 2017, 12:44
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

Director
Director
avatar
S
Joined: 07 Dec 2014
Posts: 713
Re: Working alone, printers X, Y, and Z can do a certain [#permalink]

Show Tags

New post 08 Jun 2017, 14:03
prude_sb wrote:
Working alone, printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 15, and 18 hours, respectively. What is the ratio of the time it takes printer X to do the job, working alone at its rate, to the time it takes printers Y and Z to do the job, working together at their individual rates ?

(A) 4/11
(B) 1/2
(C) 15/22
(D) 22/15
(E) 11/4


ratio of X/(Y+Z) rates=1/4/(1/5+1/6)=15/22
inverting, ratio of X/(Y+Z) times=22/15
D
Re: Working alone, printers X, Y, and Z can do a certain   [#permalink] 08 Jun 2017, 14:03
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic Dan can do a job alone in 15 hours. Fred, working alone, can do the sa Bunuel 5 15 May 2016, 14:25
1 Experts publish their posts in the topic Working alone, machine X can manufacture 1,000 nails in 12 hours. Work Bunuel 4 29 Dec 2015, 11:12
3 Experts publish their posts in the topic A person x working alone can complete a work in 10 days. A person Y .. anurag356 3 27 Jun 2015, 01:53
32 Experts publish their posts in the topic Working alone, Printers X, Y, and Z can do a certain printin Bunuel 17 08 Jun 2017, 17:06
11 While working alone at their constant rates computer X can process 240 Baten80 12 29 Jun 2016, 11:03
Display posts from previous: Sort by

Working alone, printers X, Y, and Z can do a certain

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


cron

GMAT Club MBA Forum Home| About| 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®.