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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Working alone, printers X, Y, and Z can do a certain [#permalink]
27 Jan 2007, 15:12

2

This post received KUDOS

2

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

55% (hard)

Question Stats:

61% (02:25) correct
39% (01:20) wrong based on 189 sessions

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 ?

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

Re: Working alone, printers X, Y, and Z can do a certain [#permalink]
24 Jan 2013, 03:23

Thanks for your fast reply Karishma,

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, 05:04, edited 1 time in total.

Re: Working alone, printers X, Y, and Z can do a certain [#permalink]
24 Jan 2013, 03:40

Expert's post

leventg wrote:

Thanks for your fast reply Karishma,

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).

Re: Working alone, printers X, Y, and Z can do a certain [#permalink]
19 Jan 2015, 12:29

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. _________________

Well, I’ve had a busy month! In February I traveled to interview and visit three MBA programs. Earlier in the month I also went to Florida on vacation. This...

One of the reasons why I even considered Tepper is the location. Last summer I stopped in Pittsburgh on the way home from a road trip. We were vacationing...