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 500,000 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:

82% (02:39) correct
18% (02:36) wrong based on 341 sessions

HideShow timer Statistics

Machines A, B, and C can either load nails into a bin or unload nails from that bin. Each machine works at a constant rate that is the same for loading and for unloading, although the individual machines may have different rates. Working together to load at their respective constant rates, machines A and B can load the bin in 6 minutes. Likewise, working together to load at their respective constant rates, machines B and C can load the bin in 9 minutes. How long will it take machine A to load the bin if machine C is simultaneously unloading the bin?

A - C= 5.55% That means A's loading and C's unloading together complete 5.55% of work in a minute.

100% of work will take 18 mins (100/5.55).

PS - I have been solving all Work Rate problems in this forum since morning with percentage approach and I found each one of them quite simple to solve using percentages. I don't have time else I would have submitted solutions for each problem.

A - C= 5.55% That means A's loading and C's unloading together complete 5.55% of work in a minute.

100% of work will take 18 mins (100/5.55).

PS - I have been solving all Work Rate problems in this forum since morning with percentage approach and I found each one of them quite simple to solve using percentages. I don't have time else I would have submitted solutions for each problem.

_________

Ravender Pal Singh

You dont really have to convert fractions into percentages as it can be extremely time consuming.

A - C= 5.55% That means A's loading and C's unloading together complete 5.55% of work in a minute.

100% of work will take 18 mins (100/5.55).

PS - I have been solving all Work Rate problems in this forum since morning with percentage approach and I found each one of them quite simple to solve using percentages. I don't have time else I would have submitted solutions for each problem.

_________

Ravender Pal Singh

You dont really have to convert fractions into percentages as it can be extremely time consuming.

I have just given detailed explanation for your understanding. There is no sense in calculating 100/5.55 as it is pretty obvious that it would be slightly less than 20 (range in between 16.66 - 20). The best thing about GMAT is that one need not do the complete calculation to solve the question. Once you get the equation, one can easily guess the answer as GMAT has answer options in a good range. Instead of having equations in inverted ratios, if we can have linear equations at one go, solution becomes very simple to correctly guess. I have solved so many questions till now and none of them took more than 1-2 mins.

Re: Machines A, B, and C can either load nails into a bin or [#permalink]

Show Tags

15 Nov 2012, 23:52

\(\frac{1}{A}+\frac{1}{B}=\frac{1}{T}\)

It takes A units of time for A to do it alone. It takes B units of time for B to do it alonge. BUT this means it takes T units of time for A and B to accomplish the work where A>T and B>T.

My Solution: \(\frac{1}{Amin}+\frac{1}{Bmin}=\frac{1}{6min}\) \(\frac{1}{Bmin}+\frac{1}{Cmin}=\frac{1}{9min}\)

Combine the two equations: \(\frac{1}{Amin}+\frac{1}{Bmin}-\frac{1}{Bmin}-\frac{1}{Cmin}=\frac{1}{6}-\frac{1}{9}\)

\(\frac{1}{Amin}-\frac{1}{Cmin}=1/18min\)

This means A would do 18 minutes of loading while C would do 18 minutes of unloading to complete the task.

Re: Machines A, B, and C can either load nails into a bin or [#permalink]

Show Tags

25 Sep 2013, 21:25

This took a lot of time.

We can use RTW chart, rate * time = work

Combined rate of A/B => 1/A + 1/B = (A+B)/AB

Rate * time = Work

(A+B)/AB * tab = 1 => tab = AB/(A+B) = 6

Getting A in terms of B => A = 6B/(B-6) ..... (1)

Similarly BC/(B+C) = 9

Getting C in terms of B

C = 9B/(B-9)..... (2)

A is loading and C is unloading hence

1/A - 1/C => tac = AC/(C-A)

Substituting values from (1) and (2) we get 18 _________________

Rgds, TGC! _____________________________________________________________________ I Assisted You => KUDOS Please _____________________________________________________________________________

Re: Machines A, B, and C can either load nails into a bin or [#permalink]

Show Tags

15 Dec 2014, 14:12

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. _________________

Re: Machines A, B, and C can either load nails into a bin or [#permalink]

Show Tags

16 Dec 2014, 22:39

Bunuel wrote:

Machines A, B, and C can either load nails into a bin or unload nails from that bin. Each machine works at a constant rate that is the same for loading and for unloading, although the individual machines may have different rates. Working together to load at their respective constant rates, machines A and B can load the bin in 6 minutes. Likewise, working together to load at their respective constant rates, machines B and C can load the bin in 9 minutes. How long will it take machine A to load the bin if machine C is simultaneously unloading the bin?

Re: Machines A, B, and C can either load nails into a bin or [#permalink]

Show Tags

06 Mar 2016, 08:48

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. _________________

Check out this awesome article about Anderson on Poets Quants, http://poetsandquants.com/2015/01/02/uclas-anderson-school-morphs-into-a-friendly-tech-hub/ . Anderson is a great place! Sorry for the lack of updates recently. I...

As you leave central, bustling Tokyo and head Southwest the scenery gradually changes from urban to farmland. You go through a tunnel and on the other side all semblance...

Ghibli studio’s Princess Mononoke was my first exposure to Japan. I saw it at a sleepover with a neighborhood friend after playing some video games and I was...