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:

A furniture manufacturer has two machines, but only one can [#permalink]
07 Jan 2011, 10:33

3

This post received KUDOS

5

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

85% (hard)

Question Stats:

57% (03:46) correct
43% (02:23) wrong based on 395 sessions

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

14 13 11 9 7

Machine A needs 12 days * 2 shifts = 24 shifts to do the whole job; Machine B needs 15 days * 2 shifts = 30 shifts to do the whole job;

In one day each machine works 1.5 shifts (3/2 shifts), doing (3/2)/24+(3/2)/30)=9/80 th of the whole job in one day, thus with the current work schedule they'll need 80/9=~9 days.

Re: A furniture manufacturer has two machines, but only one can [#permalink]
31 May 2013, 18:42

4

This post received KUDOS

rtaha2412 wrote:

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

A. 14 B. 13 C. 11 D. 9 E. 7

Machine A: 12 days to complete task working two shifts -> 24 days working one shift -> 48 days working half shifts Machine B: 15 days to complete task working two shifts -> 30 days working one shift -> 60 days working half shifts

In one day, each works 3 half shifts, so: 3 * (1/48 + 1/60) -> 1/16 + 1/20 = 9/80 of job per day, so ~ 9 days to complete total job.

Re: A furniture manufacturer has two machines, but only one can [#permalink]
01 Jun 2013, 00:04

1

This post received KUDOS

Quote:

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

A. 14 B. 13 C. 11 D. 9 E. 7

Let us look for LCM f 15 and 12. Say 60 is total work. A completes in 12 days 2 shifts which means it works 2.5 hrs per shift. (60/12 = 5 hrs two shifts) Similarly B completes in 15 days or works 2 hrs per shift. Now, per day work as per shift plan 2.5 (A) + 2 (B) + (2.5 + 2)/2 (A and B combined) = 6.75 hrs per day Total time = 60/6.75 which comes around 9 days. _________________

Re: A furniture manufacturer has two machines, but only one can [#permalink]
20 Nov 2013, 09:41

1

This post received KUDOS

rtaha2412 wrote:

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

A. 14 B. 13 C. 11 D. 9 E. 7

I actually got one of these right!!!!!!!!!!!!!!!! First time in about 80 attempts at a work rate problem! I'm so happy

So based on the info given, it takes 24 shifts for A to complete the job, and 30 shifts for B to complete the job, if they each worked independently. So the rate for A is 1/24 and for B 1/30. If each day they're working 1.5 shifts, then each day A completes 1.5/24 (which equals 1/16) and B is completing 1.5/30 (which equals 20). Finding a common denominator of 80, their total work per day combined is 9/80. Thus after working 1.5 shifts each per day for 9 days they'll have completed the whole job (8/9ths through the 9th day).

Re: A furniture manufacturer has two machines, but only one can [#permalink]
25 Dec 2013, 23:04

Expert's post

curious why some questions will specify an "approx" solution and provide rounded answer choices, others will not, however provide fractional answers (when applicable), and then others, such as above, will do neither/both? I understand the above job wasn't done until partly into the 8th day, so it did take 9 days to complete...

Bunuel, is a question such as the above fair game on the test? I have been under the impression that the answer choices will be exact, unless the question specifies an "approx" solution or the answer choices are based on objects that can't be physically split (people, cars, etc)...isn't a day an interval and/or unit of measure? thank you. _________________

Re: A furniture manufacturer has two machines, but only one can [#permalink]
25 Dec 2013, 23:59

rtaha2412 wrote:

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

A. 14 B. 13 C. 11 D. 9 E. 7

Let us say that the total work is of 240 units

A ---- 12 days ---- 2 shifts ----- 10 units per shift

B ---- 15 days ---- 2 shifts ----- 8 units per shift

When they work together A + B + (A+B)/2 = 10 + 8 + 9 = 27 units per shift

Every 3 shifts ---- 27 units x 8 x 8

Every 24 shifts ---- 216 units

26 shifts ----- 216 + 18 = 234

In 27th shift the work will get finishe

1 Day ---- 3 shifts hence total days taken = 27/3 = 9 days

Re: A furniture manufacturer has two machines, but only one can [#permalink]
26 Dec 2013, 00:46

rtaha2412 wrote:

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

A. 14 B. 13 C. 11 D. 9 E. 7

The clause "while both work half of the third shift" is confusing. The phrase "each work half of the third phrase" would have had more clarity.

Re: A furniture manufacturer has two machines, but only one can [#permalink]
08 Jan 2014, 21:17

1

This post received KUDOS

Expert's post

TooLong150 wrote:

This question should have asked "approximately" how many days will it take for the machines to do the job.

'Approximately' could actually make such a question ambiguous. Not this one though but a similar question with the answer as 9.2 days. You round off 8.89 days as 9 days and everything is fine in this question. What do you do when you get 9.2 days? Do you need 9 days or 10 days? Can you round off 9.2 as 9 even though that is what you do with numbers? No, because in 9 days your work is not over. You do need 10 days.

To finish a work say you need to work full 9 days and a part of the 10th day. If I ask you how many days do you need to complete the work, will you say 9 or 10? You will say 10 even if you don't use the 10th day fully. _________________

Re: A furniture manufacturer has two machines, but only one can [#permalink]
08 Jan 2014, 22:26

2

This post received KUDOS

rtaha2412 wrote:

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

A. 14 B. 13 C. 11 D. 9 E. 7

in one shift, A can do 1/24 of the work in one shift, B can do 1/30 of the work no of days required for the completion of the task by A and B together in the current schedule is (3/2)*((1/24)+(1/30))*t=1 t=8.888=9

Re: A furniture manufacturer has two machines, but only one can [#permalink]
28 Mar 2015, 13:34

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. _________________

The Stanford interview is an alumni-run interview. You give Stanford your current address and they reach out to alumni in your area to find one that can interview you...

Originally, I was supposed to have an in-person interview for Yale in New Haven, CT. However, as I mentioned in my last post about how to prepare for b-school interviews...

Interested in applying for an MBA? In the fourth and final part of our live QA series with guest expert Chioma Isiadinso, co-founder of consultancy Expartus and former admissions...