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:

Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
17 Apr 2010, 04:27

1

This post received KUDOS

7

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

75% (hard)

Question Stats:

46% (02:22) correct
54% (01:40) wrong based on 129 sessions

Crew A can build a complete car in 20 minutes and Crew B can build a complete car in 25 minutes. If both crews work independently and start at the same time, what is the shortest amount of time it could take for 10 cars to be complete?

A. 111 1/9 minutes B. 115 2/5 minutes C. 116 minutes D. 120 minutes E. 125 minutes

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
17 Apr 2010, 04:53

IMO D

because in 100 min both crew will complete 9 cars (5 by crew A and 4 by crew B) then crew a will finish the 10th car in next 20 min (before crew B which will complete their next care in 25 min, 5 min more than A)

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
17 Apr 2010, 05:41

hardnstrong wrote:

IMO D

because in 100 min both crew will complete 9 cars (5 by crew A and 4 by crew B) then crew a will finish the 10th car in next 20 min (before crew B which will complete their next care in 25 min, 5 min more than A)

Hope this helps

I just overlooked this "independently" clause. Just did the 1/20+1/25 thing... Thank you-

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
19 Apr 2010, 10:23

please forgive me....but would you mind spelling out why working independently has an effect? Unfortunately I still don't get it.....even if they work independently, aren't at total of 10 cars completed between the two of them? Thanks

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
19 Apr 2010, 10:24

please forgive me....but would you mind spelling out why working independently has an effect? Unfortunately I still don't get it.....even if they work independently, aren't at total of 10 cars completed between the two of them? Thanks

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
19 Apr 2010, 10:38

PeterFaulkner wrote:

please forgive me....but would you mind spelling out why working independently has an effect? Unfortunately I still don't get it.....even if they work independently, aren't at total of 10 cars completed between the two of them? Thanks

welll, A can build a car in 20 minutes and B in 25. So if they both utilize their production capabilities and work on a single car together, this should logically take less than 20 minutes for sure. (Think of it like, A is working on a car and B is helping A at the same time- this should definitely take way less then 20 minutes...) mathematically: it's 1/20+1/25=9/100 where it takes 100/9 hours to build a single car. Thus it takes 111 1/9 hours to complete 10 of them. And here you go- the guys put this one into the very first choice so that you'll fall into that trap!

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
19 Apr 2010, 11:26

I strongly dislike this question. If we’re to assume that rates can be fractional then why can’t the same be assumed for work also? I wonder if the GMAC would put something this ambiguous on the real test. _________________

He that is in me > he that is in the world. - source 1 John 4:4

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
20 Apr 2010, 00:46

widerangeinput wrote:

Crew A can build a complete car in 20 minutes and Crew B can build a complete car in 25 minutes. If both crews work independently and start at the same time, what is the shortest amount of time it could take for 10 cars to be complete?

A. 111 1/9 minutes B. 115 2/5 minutes C. 116 minutes D. 120 minutes E. 125 minutes

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
20 Apr 2010, 03:55

if the question said 10 whole cars then i'd say "okay that makes sense" but even from an accounting perspective inventory is recorded by the percentage of its completion and added up (not that that applies here. i'm just saying that there is nothing that explicitly states that it doesn't apply.) _________________

He that is in me > he that is in the world. - source 1 John 4:4

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
20 Apr 2010, 04:23

hardnstrong wrote:

widerangeinput wrote:

Crew A can build a complete car in 20 minutes and Crew B can build a complete car in 25 minutes. If both crews work independently and start at the same time, what is the shortest amount of time it could take for 10 cars to be complete?

A. 111 1/9 minutes B. 115 2/5 minutes C. 116 minutes D. 120 minutes E. 125 minutes

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
10 May 2011, 09:27

Take the one that needs less time i.e. 20 min... 20 min*5 = 100 min So total 9 cars can be made in 100 min (5 from A and 4 from B) So one more car would need 20 more min

Re: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
15 Oct 2014, 10:19

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: Crew A can build a complete car in 20 minutes and Crew B can build a [#permalink]
15 Oct 2014, 12:13

widerangeinput wrote:

Crew A can build a complete car in 20 minutes and Crew B can build a complete car in 25 minutes. If both crews work independently and start at the same time, what is the shortest amount of time it could take for 10 cars to be complete?

A. 111 1/9 minutes B. 115 2/5 minutes C. 116 minutes D. 120 minutes E. 125 minutes

Ha Ha Ha Ha..

Awesome question. Its easy and has a trap. I fell into it. As soon as I read Time taken to complete cars, started solving by Work ratio method...

Later on realized my mistake... _________________

Give KUDOS if the post helps you...

gmatclubot

Re: Crew A can build a complete car in 20 minutes and Crew B can build a
[#permalink]
15 Oct 2014, 12:13

On September 6, 2015, I started my MBA journey at London Business School. I took some pictures on my way from the airport to school, and uploaded them on...

When I was growing up, I read a story about a piccolo player. A master orchestra conductor came to town and he decided to practice with the largest orchestra...

I’ll start off with a quote from another blog post I’ve written : “not all great communicators are great leaders, but all great leaders are great communicators.” Being...