GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 16 Dec 2018, 23:33

### 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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### 10 Keys to nail DS and CR questions

December 17, 2018

December 17, 2018

06:00 PM PST

07:00 PM PST

Join our live webinar and learn how to approach Data Sufficiency and Critical Reasoning problems, how to identify the best way to solve each question and what most people do wrong.
• ### R1 Admission Decisions: Estimated Decision Timelines and Chat Links for Major BSchools

December 17, 2018

December 17, 2018

10:00 PM PST

11:00 PM PST

From Dec 5th onward, American programs will start releasing R1 decisions. Chat Rooms: We have also assigned chat rooms for every school so that applicants can stay in touch and exchange information/update during decision period.

# Working at their respective constant rates, printing machine X, Y, and

Author Message
TAGS:

### Hide Tags

Manager
Joined: 10 Feb 2011
Posts: 108
Working at their respective constant rates, printing machine X, Y, and  [#permalink]

### Show Tags

Updated on: 24 Apr 2015, 07:31
1
10
00:00

Difficulty:

15% (low)

Question Stats:

79% (01:20) correct 21% (01:58) wrong based on 228 sessions

### HideShow timer Statistics

Working at their respective constant rates, printing machine X, Y, and Z can finish a certain work in 9, 12, and 18 hours. If three machines work together to finish the work, what fraction of the work will be finished by the machine Z?

(A) 4/9
(B) 1/3
(C) 1/4
(D) 2/9
(E) 1/9

Originally posted by banksy on 17 Feb 2011, 14:11.
Last edited by Bunuel on 24 Apr 2015, 07:31, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8678
Location: Pune, India
Re: Working at their respective constant rates, printing machine X, Y, and  [#permalink]

### Show Tags

17 Feb 2011, 18:47
6
2
banksy wrote:
192. Working at their respective constant rates, printing machine X, Y, and Z can finish a certain work in 9, 12, and 18 hours. If three machines work together to finish the work, what fraction of the work will be finished by the machine Z?
(A)
(B)
(C)
(D)
(E)

Since time taken by X, Y and Z is in the ratio 9:12:18 i.e. 3:4:6,
their speeds are in the ratio $$\frac{1}{3}:\frac{1}{4}:\frac{1}{6} = 4:3:2$$
So Z will do $$\frac{2}{(4+3+2)} = 2/9$$ of the work
_________________

Karishma
Veritas Prep GMAT Instructor

Retired Moderator
Joined: 20 Dec 2010
Posts: 1820
Re: Working at their respective constant rates, printing machine X, Y, and  [#permalink]

### Show Tags

18 Feb 2011, 00:48
7
X; 9 hour-> 1 work
=> 1 hour -> 1/9 work

Y; 12 hour-> 1 work
=> 1 hour-> 1/12 work

Z; 18 hour-> 1 work
=> 1 hour-> 1/18 work

Total work done by all machines in 1 hour;
1/9+1/12+1/18 = (4+3+2)/36=9/36=1/4 work

Jointly;
1/4 work-> 1 hour
1 work-> 1/(1/4) = 4 hours(Jointly X,Y,Z all spent for 4 hours towards completing the job)

We know from before;
Z; 18 hour-> 1 work
=> 1 hour-> 1/18 work

If Z can perform 1/18 work in 1 hour;
In 4 hours, he would have performed
(1/18)*4 work
2/9 work

Ans: 2/9
_________________
##### General Discussion
Math Expert
Joined: 02 Sep 2009
Posts: 51233
Re: Working at their respective constant rates, printing machine X, Y, and  [#permalink]

### Show Tags

17 Feb 2011, 15:02
2
2
banksy wrote:
192. Working at their respective constant rates, printing machine X, Y, and Z can finish a certain work in 9, 12, and 18 hours. If three machines work together to finish the work, what fraction of the work will be finished by the machine Z?
(A)
(B)
(C)
(D)
(E)

In 1 hour X can finish 1/9=4/36 of the work, Y can finish 1/12=3/36 of the work and Z can finish 1/18=2/36 of the work. So in 1 hour out of 4+3+2=9 parts of the work Z finished 2 parts or 2/9 of the work.

Or if Z can do 1 part in some time interval then in the same time interval X can do 2 parts (as its rate is twice the rate of Z), and Y can do 1.5 parts (again as its rate is 1.5 times the rate of Z) so share of Z is 1 out of 1+2+1.5=4.5, or 1/4.5=2/9.

_________________
Manager
Joined: 16 Mar 2016
Posts: 129
Location: France
GMAT 1: 660 Q47 V33
GPA: 3.25
Re: Working at their respective constant rates, printing machine X, Y, and  [#permalink]

### Show Tags

03 May 2016, 12:59
The fraction of the work performed by Z is :

Rz / (Rx + Ry + Rz) = (1/18) / (1/9 + 1/12 + 1/18) = (1/18)/(1/4) = 2/9
Non-Human User
Joined: 09 Sep 2013
Posts: 9194
Re: Working at their respective constant rates, printing machine X, Y, and  [#permalink]

### Show Tags

29 Nov 2018, 08:22
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: Working at their respective constant rates, printing machine X, Y, and &nbs [#permalink] 29 Nov 2018, 08:22
Display posts from previous: Sort by