Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

og math # 130

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 28
Joined: Thu May 19, 2011 8:47 am

by shingik » Tue Jul 12, 2011 3:02 pm
BTW --work problems are just one of those you should know the formula to solving for time (TIME A * TIME B divided by TIME A + TIME B) when given discrete simultaneous rates. Read up on this because it will save you a bunch of time from trying to figure out what the heck will be going on with which rate etc. It's kinda like triangle problems. You will eventually solve them but you really should not be inventing the wheel during the test. I think the GMAT just wants you to be able to recognize which type of problem you are working with and apply very simple mathematics.
Top
Join the discussion
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Tue Jul 12, 2011 9:50 pm

by raamjee » Tue Jul 12, 2011 9:52 pm
rate o x= 1/12
rate of y and z combined = 1/15+1/18 = 33/15.18

ratios is

22/15

option is D
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 11
Joined: Tue Jul 19, 2011 12:01 am

by astvansh » Thu Jul 21, 2011 12:53 am
c
Top
Join the discussion
User avatar
Senior | Next Rank: 100 Posts
Posts: 54
Joined: Sun Nov 29, 2009 7:11 pm
Location: Bangalore
Thanked: 4 times

by abhisays » Tue Jul 26, 2011 12:36 am
The answer is D.
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 31
Joined: Thu Aug 12, 2010 12:40 amFollowed by: 1 member
Thanked: 1 times

by olegpoi » Thu Jul 28, 2011 11:45 am
D 22/15
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 14
Joined: Sun Aug 14, 2011 4:25 am
Thanked: 1 times

by ashhchdg » Tue Aug 16, 2011 3:32 pm
D 22/15

X does 1/12th of work in an hour.
Y+Z together do 1/18 and 1/15 of work together in an hour.
Simplifying they both together do 11/90 th of work.
Therefore they will complete the work in 90/11 if they work together

now the ratio asked is (12*11)/90---->22/15
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 23
Joined: Sat Aug 20, 2011 3:58 am

by JS_2 » Mon Aug 22, 2011 10:21 pm
22/15
Just reverse the time to rate for Y & Z. add the rates 1/y+1/z
Then reciprocal of 1/y and 1/x gives time taken by y and z together to complete the job..
Thats it..Ans = time taken by x/time taken by y and z together.
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 53
Joined: Sun Apr 10, 2011 12:15 pm
Thanked: 1 times

by Deependra1 » Tue Aug 23, 2011 7:47 pm
ANSWER: D
Top
Join the discussion
User avatar
Legendary Member
Posts: 540
Joined: Sat Dec 20, 2008 7:24 pmFollowed by: 6 members
Thanked: 37 times

by navami » Thu Sep 08, 2011 12:29 pm
22/15
This time no looking back!!!
Navami
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 197
Joined: Thu Sep 15, 2011 10:22 amFollowed by: 2 members
Thanked: 6 times

by parul9 » Sun Sep 18, 2011 9:42 am
The answer is D.
However, I got it wrong. Thought it to be C.
Thought we had to find the ratio of rates and not the total time!

Key Takeaway: *Read* the question! X-(
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Mon Sep 26, 2011 6:34 pm

by way2ashish » Tue Sep 27, 2011 8:59 am
Correct answer is definitely D
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 37
Joined: Mon Oct 10, 2011 2:27 am
Thanked: 2 times

by ritzzzr » Tue Oct 11, 2011 10:23 pm
Work done by x in 1 hour = 1/12
Work done by y and z in 1 hour = 1/15+1/18=11/90

so total time taken by both to complete the job =90/11 hrs

time taken by x /time taken by a & b = 18/(90/11)=22/15


resilient wrote:working alone, printers x,y, and z can do a certain printing job, consisitning of a large number of pages, 12, 15, and 18 hours, respectively. What is the ratio of the time it takes printer x to do the job, working at its rate, to time it takes printers y and z to do the job, working together at their individual rates?

a. 4/11
b.1/2
c. 15/22
d.22/15
e.11/4

qa is d. I dont see why C is wrong. I dont see why the solution flips the combined rate of y and z working together. help stuart?
Top
Join the discussion
Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Wed Mar 10, 2010 5:00 pm

by olylo » Thu Oct 13, 2011 1:25 am
Answer is 22/15
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 11
Joined: Sat Oct 15, 2011 8:51 pm
Thanked: 1 times

by dvinoth86 » Mon Oct 17, 2011 9:45 am
Best way to save time on such problems is to remove the fraction part by assuming the work as a LCM of the time taken to complete the work and then find individual work done/unit time. This has been explained earlier by Farooq.

Working with numbers definitely saves time when compared to working with fractions
Top
Join the discussion
User avatar
Legendary Member
Posts: 588
Joined: Sun Oct 16, 2011 9:42 amFollowed by: 9 members
Location: New Delhi, India
Thanked: 130 times
GMAT Score:720

by rijul007 » Tue Oct 18, 2011 7:38 pm
Let us say the printer needs to print 180 pages.
Then,
the rate at which printer x works => 180/12 => 15 pages/hr
the rate at which printer y works => 180/15 => 12 pages/hr
the rate at which printer z works => 180/18 => 10 pages/hr
the rate at which printers y and z work => 10+12 => 22 pages/h

ratio of time taken by printer x to printer y and z together => (180/15)/(180/22) => 22/15
Top
Join the discussion