Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 22 May 2017, 18:23

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# It takes printer A 4 more minutes than printer B to print 40

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Current Student
Joined: 11 May 2008
Posts: 556
Followers: 8

Kudos [?]: 190 [0], given: 0

It takes printer A 4 more minutes than printer B to print 40 [#permalink]

### Show Tags

30 Aug 2008, 02:22
1
This post was
BOOKMARKED
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

It takes printer A 4 more minutes than printer B to print 40 pages. Working together, the two printers can print 50 pages in 6 minutes. How long will it take printer A to print 80 pages?

* 12
* 18
* 20
* 24
* 30
Director
Joined: 23 Sep 2007
Posts: 787
Followers: 5

Kudos [?]: 192 [0], given: 0

Re: time and work [#permalink]

### Show Tags

30 Aug 2008, 14:06
arjtryarjtry wrote:
It takes printer A 4 more minutes than printer B to print 40 pages. Working together, the two printers can print 50 pages in 6 minutes. How long will it take printer A to print 80 pages?

* 12
* 18
* 20
* 24
* 30

D

tough question for setting up a formula, took me forever

I solved this by substitution in reverse

For printer A:
24min --> 80 pages
6min --> 20 pages

If A takes 24 minutes to print 80 page, then for printer B
16min --> 80 pages
8min --> 40 pages
6min --> 30 pages

30 + 20 = 50 pages in 6 minutes
Manager
Joined: 28 Jul 2004
Posts: 136
Location: Melbourne
Schools: Yale SOM, Tuck, Ross, IESE, HEC, Johnson, Booth
Followers: 1

Kudos [?]: 66 [0], given: 2

Re: time and work [#permalink]

### Show Tags

30 Aug 2008, 16:58
Here's the explanation;

For 40 pages

t[a] - t[b] = 4 min --> t[b] = t[a] + 4 ----- (1)

For 50 pages A and B take 6 min --> For 40 pages A and B takes 6/50*40 = 24/5 minutes

Now the equation when both A and B work together to finish a task is : t[a]*t[b]/(t[a] + t[b]) ----- (2)

Putting t[b] = t[a] + 4 from (1) equation (2) becomes:

5t[a]^2 - 68t[a] + 96 = 0 --> (5t[a]-8)(t[a]-12) = 0

---> t[a] = 12 (I discarded t[a] = 8/5 looking at the answer but not sure why it has to be excluded)

So, for 40 pages A takes 12 minutes ---> for 80 pages it will take 24 minutes!
_________________

kris

Current Student
Joined: 11 May 2008
Posts: 556
Followers: 8

Kudos [?]: 190 [0], given: 0

Re: time and work [#permalink]

### Show Tags

30 Aug 2008, 19:49
for the GMAT , i think back solving is best...
but if the desire to display one's equation forming prowess is high..,
then resort to the conventional method.
the ans is D..
Re: time and work   [#permalink] 30 Aug 2008, 19:49
Display posts from previous: Sort by

# It takes printer A 4 more minutes than printer B to print 40

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.