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

It is currently 23 Jul 2014, 20:48

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 more minutes more than printer B to

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 12 Feb 2006
Posts: 117
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
It takes printer A 4 more minutes more than printer B to [#permalink] New post 21 Feb 2007, 03:53
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  55% (medium)

Question Stats:

56% (04:22) correct 44% (03:29) wrong based on 61 sessions
It takes printer A 4 more minutes more 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?

A. 12
B. 18
C. 20
D. 24
E. 30

Open discussion of this question is here: it-takes-printer-a-4-more-minutes-than-printer-b-to-print-98479.html
[Reveal] Spoiler: OA

Last edited by Bunuel on 20 Mar 2012, 13:33, edited 1 time in total.
Topic is locked.
Kaplan GMAT Prep Discount CodesKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
1 KUDOS received
Director
Director
User avatar
Joined: 05 Feb 2006
Posts: 904
Followers: 1

Kudos [?]: 24 [1] , given: 0

GMAT Tests User
 [#permalink] New post 21 Feb 2007, 05:18
1
This post received
KUDOS
My answer is D.
Did it by picking the answer first and testing it.... Did not take very long.... :)

We start the other way round. We say that printer A can print 80 pages in 24 minutes, then we can imply its rate:

r*24=80
r=80/24=10/3

Then, we test this rate to determine how many minutes it will take to print 40 pages:

10/3*t=40
t=12 minutes

Then printer B must have printed 40 pages in 8 minutes. Knowing this, we can determine the implied rate of B.

r*8=40
r=40/8=5

Now calculate the common rate: 10/3+5=25/3
And test it whether it works with the stated evidence, that those two printers working together can print 50 pages in 6 minutes:

25/3*6=50... it does work.


I started the values from choice C, after that you know which way to go, up or down :)
SO maximum you have to test two values.

Last edited by SimaQ on 21 Feb 2007, 05:33, edited 1 time in total.
2 KUDOS received
GMAT Instructor
avatar
Joined: 04 Jul 2006
Posts: 1270
Location: Madrid
Followers: 23

Kudos [?]: 113 [2] , given: 0

Re: Printer Work Problem [#permalink] New post 21 Feb 2007, 05:32
2
This post received
KUDOS
bz9 wrote:
It takes printer A 4 more minutes more 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?

a. 12
b. 18
c. 20
d. 24
e. 30


If it takes 4 more minutes for A to print 40 pages than it takes B,
it takes 5 more minutes for A to print 50 pages than it takes B.

Thus if b is the number of minutes than B takes to print 50 pages,
we can write:

1/b+1/(b+5)=1/6 (since in 1 minute, they print 1/6th of the 50 page job)

6(2b+5)=b(b+5)

b^2-7b-30=0
(b-10)(b+3)=0

b=10

Thus it takes A 15 minutes to print 50 pages and 15*80/50=24 minutes to print 80 pages
VP
VP
User avatar
Joined: 09 Jan 2007
Posts: 1045
Location: New York, NY
Schools: Chicago Booth Class of 2010
Followers: 10

Kudos [?]: 156 [0], given: 3

GMAT Tests User
 [#permalink] New post 21 Feb 2007, 06:11
It is easy to pick the answers and make the back solving, but the direct solve would be:

A => 40/(T+4) pg/min
B => 40/T pg/min
A+B => 50/6 pg/min

So: 40/(T+4) + 40/T = 50/6
with some algebra (T-8)*(5T+12)=0 so T=8min or T=-12/5min
Taking the T=8, A makes 40 pages in 12 min (8+4), and would take then 24 min to make 80pgs.
Manager
Manager
avatar
Joined: 12 Feb 2006
Posts: 117
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
 [#permalink] New post 22 Feb 2007, 20:45
D is the OA,

I like the way Kevin did it by spotting the rate for 50 pages.

Half the battle is spotting that.
Intern
Intern
avatar
Joined: 16 Nov 2009
Posts: 7
Followers: 0

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

Re: Printer Work Problem [#permalink] New post 20 Mar 2012, 13:23
kevincan wrote:
bz9 wrote:
It takes printer A 4 more minutes more 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?

a. 12
b. 18
c. 20
d. 24
e. 30


If it takes 4 more minutes for A to print 40 pages than it takes B,
it takes 5 more minutes for A to print 50 pages than it takes B.

Thus if b is the number of minutes than B takes to print 50 pages,
we can write:

1/b+1/(b+5)=1/6 (since in 1 minute, they print 1/6th of the 50 page job)

6(2b+5)=b(b+5)

b^2-7b-30=0
(b-10)(b+3)=0

b=10

Thus it takes A 15 minutes to print 50 pages and 15*80/50=24 minutes to print 80 pages


Kevin,

Would you please show me how you arrive 'If it takes 4 more minutes for A to print 40 pages than it takes B,
it takes 5 more minutes for A to print 50 pages than it takes B.'?

Thanks
Phuoc
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18707
Followers: 3237

Kudos [?]: 22288 [0], given: 2611

Re: Printer Work Problem [#permalink] New post 20 Mar 2012, 13:32
Expert's post
Minhphuoc wrote:
kevincan wrote:
bz9 wrote:
It takes printer A 4 more minutes more 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?

a. 12
b. 18
c. 20
d. 24
e. 30


If it takes 4 more minutes for A to print 40 pages than it takes B,
it takes 5 more minutes for A to print 50 pages than it takes B.

Thus if b is the number of minutes than B takes to print 50 pages,
we can write:

1/b+1/(b+5)=1/6 (since in 1 minute, they print 1/6th of the 50 page job)

6(2b+5)=b(b+5)

b^2-7b-30=0
(b-10)(b+3)=0

b=10

Thus it takes A 15 minutes to print 50 pages and 15*80/50=24 minutes to print 80 pages


Kevin,

Would you please show me how you arrive 'If it takes 4 more minutes for A to print 40 pages than it takes B,
it takes 5 more minutes for A to print 50 pages than it takes B.'?

Thanks
Phuoc


4 more minutes to print 40 pages --> in 1 more minutes 40/4=10 pages --> so in 5 more minutes 5*10 pages.

Complete solution:
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?
A. 12
B. 18
C. 20
D. 24
E. 30

Let the time needed to print 40 pages for printer A be a minutes, so for printer B it would be a-4 minutes.

The rate of A would be rate=\frac{job}{time}=\frac{40}{a} pages per minute and the rate of B rate=\frac{job}{time}=\frac{40}{a-4} pages per minute.

Their combined rate would be \frac{40}{a}+\frac{40}{a-4} pages per minute. Also as "two printers can print 50 pages in 6 minutes" then their combined rate is rate=\frac{job}{time}=\frac{50}{6}, so \frac{40}{a}+\frac{40}{a-4}=\frac{50}{6}.

\frac{40}{a}+\frac{40}{a-4}=\frac{50}{6} --> \frac{1}{a}+\frac{1}{a-4}=\frac{5}{24}. At this point we can either try to substitute the values from answer choices or solve quadratic equation. Remember as we are asked to find time needed for printer A to print 80 pages, then the answer would be 2a (as a is the time needed to print 40 pages). Answer D works: 2a=24 --> a=12 --> \frac{1}{12}+\frac{1}{8}=\frac{5}{24}.

Answer: D.

In case of any question please continue the discussion here: it-takes-printer-a-4-more-minutes-than-printer-b-to-print-98479.html
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 16 Nov 2009
Posts: 7
Followers: 0

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

Re: Printer Work Problem [#permalink] New post 21 Mar 2012, 07:36
Thank you, Bunuel.


Bunuel wrote:
Minhphuoc wrote:
kevincan wrote:
It takes printer A 4 more minutes more 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?

a. 12
b. 18
c. 20
d. 24
e. 30


If it takes 4 more minutes for A to print 40 pages than it takes B,
it takes 5 more minutes for A to print 50 pages than it takes B.

Thus if b is the number of minutes than B takes to print 50 pages,
we can write:

1/b+1/(b+5)=1/6 (since in 1 minute, they print 1/6th of the 50 page job)

6(2b+5)=b(b+5)

b^2-7b-30=0
(b-10)(b+3)=0

b=10

Thus it takes A 15 minutes to print 50 pages and 15*80/50=24 minutes to print 80 pages


Kevin,

Would you please show me how you arrive 'If it takes 4 more minutes for A to print 40 pages than it takes B,
it takes 5 more minutes for A to print 50 pages than it takes B.'?

Thanks
Phuoc


4 more minutes to print 40 pages --> in 1 more minutes 40/4=10 pages --> so in 5 more minutes 5*10 pages.

Complete solution:
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?
A. 12
B. 18
C. 20
D. 24
E. 30

Let the time needed to print 40 pages for printer A be a minutes, so for printer B it would be a-4 minutes.

The rate of A would be rate=\frac{job}{time}=\frac{40}{a} pages per minute and the rate of B rate=\frac{job}{time}=\frac{40}{a-4} pages per minute.

Their combined rate would be \frac{40}{a}+\frac{40}{a-4} pages per minute. Also as "two printers can print 50 pages in 6 minutes" then their combined rate is rate=\frac{job}{time}=\frac{50}{6}, so \frac{40}{a}+\frac{40}{a-4}=\frac{50}{6}.

\frac{40}{a}+\frac{40}{a-4}=\frac{50}{6} --> \frac{1}{a}+\frac{1}{a-4}=\frac{5}{24}. At this point we can either try to substitute the values from answer choices or solve quadratic equation. Remember as we are asked to find time needed for printer A to print 80 pages, then the answer would be 2a (as a is the time needed to print 40 pages). Answer D works: 2a=24 --> a=12 --> \frac{1}{12}+\frac{1}{8}=\frac{5}{24}.

Answer: D.

In case of any question please continue the discussion here: it-takes-printer-a-4-more-minutes-than-printer-b-to-print-98479.html[/quote]
Re: Printer Work Problem   [#permalink] 21 Mar 2012, 07:36
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic It takes printer A 4 more minutes than printer B to print 40 raghavs 6 14 Feb 2010, 23:21
It takes printer A 4 more minutes than printer B to print 40 arjtryarjtry 3 30 Aug 2008, 01:22
It takes printer A 4 minutes more than printer B to print 40 marcodonzelli 4 10 Mar 2008, 22:22
It takes printer A 4 more minutes than printer B to print 40 marcodonzelli 3 02 Mar 2008, 08:04
It takes printer A 4 more minutes than printer B to print 40 beckee529 7 31 Oct 2007, 22:44
Display posts from previous: Sort by

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

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| 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®.