Find all School-related info fast with the new School-Specific MBA Forum

It is currently 06 May 2016, 05:36
GMAT Club Tests

Close

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
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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

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

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
VP
VP
avatar
Joined: 22 Nov 2007
Posts: 1092
Followers: 9

Kudos [?]: 374 [0], given: 0

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

Show Tags

New post 10 Mar 2008, 23:22
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

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

12 18 20 24 30
Director
Director
avatar
Joined: 10 Sep 2007
Posts: 947
Followers: 8

Kudos [?]: 245 [0], given: 0

Re: gmatprep work [#permalink]

Show Tags

New post 11 Mar 2008, 07:41
Printer B takes X min to print 40 pages. Per min. it can print 40/X pages.
So Printer A will take X+4 mins. to print 40 pages. Per min. it can print 40/(X+4) pages.

Given that together they can print 50 pages in 6 mins.
So 6(40/X + 40/X+4) = 50

=> 240X + 960 + 240X = 50X^2 + 200X
=> 50X^2 + 280X - 960 = 0
=> 5X^2 + 28X - 960 = 0
=> X = -2.4 which cannot be taken as X cannot be -ve and X = 8

Printer A takes 8+4 = 12 mins. to print 40 pages,
For 80 mins it will take = 2*12 = 24 mins.

Answer D.
VP
VP
avatar
Joined: 22 Nov 2007
Posts: 1092
Followers: 9

Kudos [?]: 374 [0], given: 0

Re: gmatprep work [#permalink]

Show Tags

New post 14 Mar 2008, 09:24
abhijit_sen wrote:
Printer B takes X min to print 40 pages. Per min. it can print 40/X pages.
So Printer A will take X+4 mins. to print 40 pages. Per min. it can print 40/(X+4) pages.

Given that together they can print 50 pages in 6 mins.
So 6(40/X + 40/X+4) = 50

=> 240X + 960 + 240X = 50X^2 + 200X
=> 50X^2 + 280X - 960 = 0
=> 5X^2 + 28X - 960 = 0
=> X = -2.4 which cannot be taken as X cannot be -ve and X = 8

Printer A takes 8+4 = 12 mins. to print 40 pages,
For 80 mins it will take = 2*12 = 24 mins.

Answer D.


your answer is right and I followed your method. anyway it took me more than 2 minutes. is there any shortcut? i.e. if a spends 4 minutes more than b to make 40 copies, it would spend 1 more minute to make 10 more copies so 10/x + 10/(x-1) = 50/6
let's divide both members by 10 and get 1/x + 1/(x-1) = 5/6 which makes things much easier. any other solutions?
Director
Director
avatar
Joined: 10 Sep 2007
Posts: 947
Followers: 8

Kudos [?]: 245 [0], given: 0

Re: gmatprep work [#permalink]

Show Tags

New post 14 Mar 2008, 10:50
You can use formula of quarditic equation to solve for 5X^2 + 28X - 960 = 0.

As per it X = (-28 + Sqrt((28)^2 + 4*5*960))/2*5, and (-28 - Sqrt((28)^2 + 4*5*960))/2*5
VP
VP
avatar
Joined: 22 Nov 2007
Posts: 1092
Followers: 9

Kudos [?]: 374 [0], given: 0

Re: gmatprep work [#permalink]

Show Tags

New post 14 Mar 2008, 12:26
abhijit_sen wrote:
You can use formula of quarditic equation to solve for 5X^2 + 28X - 960 = 0.

As per it X = (-28 + Sqrt((28)^2 + 4*5*960))/2*5, and (-28 - Sqrt((28)^2 + 4*5*960))/2*5


of course I can but I would avoid calculus in 2 minutes
Re: gmatprep work   [#permalink] 14 Mar 2008, 12:26
Display posts from previous: Sort by

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

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.