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

 It is currently 06 Jul 2015, 05:52

### 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

# Robots X, Y, and Z each assemble components at their

Author Message
TAGS:
Senior Manager
Joined: 28 Aug 2010
Posts: 265
Followers: 3

Kudos [?]: 198 [1] , given: 11

Robots X, Y, and Z each assemble components at their [#permalink]  03 Jan 2011, 17:30
1
KUDOS
2
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

71% (02:10) correct 29% (01:33) wrong based on 288 sessions
Robots X, Y, and Z each assemble components at their respective constant rates. If r(x) is the ratio of robot X's constant rate to robot Z's constant rate and r(y) is the ratio of robot Y's constant rate to robot Z's constant rate, is robot Z's constant rate the greatest of the three?

(1) $$r_x<r_y$$
(2) $$r_y<1$$

Can some explain the reasoning behind this ques.
[Reveal] Spoiler: OA

_________________

Gmat: everything-you-need-to-prepare-for-the-gmat-revised-77983.html
-------------------------------------------------------------------------------------------------
Ajit

Last edited by Bunuel on 08 Feb 2012, 04:09, edited 1 time in total.
Edited the question
Math Expert
Joined: 02 Sep 2009
Posts: 28323
Followers: 4482

Kudos [?]: 45338 [4] , given: 6752

Re: Robots X, Y, and Z each assemble [#permalink]  08 Feb 2012, 04:06
4
KUDOS
Expert's post
2
This post was
BOOKMARKED
Robots X, Y, and Z each assemble components at their respective constant rates. If r(x) is the ratio of robot X's constant rate to robot Z's constant rate and r(y) is the ratio of robot Y's constant rate to robot Z's constant rate, is robot Z's constant rate the greatest of the three?

Let the rates of robots X, Y, and Z be x, y, and z respectively. Given: $$r_x=\frac{x}{z}$$ and $$r_y=\frac{y}{z}$$. Question is $$z>x$$ and $$z>y$$?

(1) $$r_x<r_y$$ --> $$\frac{x}{z}<\frac{y}{z}$$ --> $$x<y$$. Not sufficient.

(2) $$r_y<1$$ --> $$\frac{y}{z}<1$$ --> $$y<z$$. Not sufficient.

(1)+(2) As $$x<y$$ and $$y<z$$ then $$x<y<z$$. Sufficient.

_________________
Manager
Joined: 17 Jul 2010
Posts: 123
Followers: 1

Kudos [?]: 29 [0], given: 43

Re: Robots X, Y, and Z each assemble components at their [#permalink]  07 May 2013, 06:09
Does this equation work when plugging in numbers, opposed to looking at pure variables?
Intern
Joined: 12 Apr 2013
Posts: 9
Location: Germany
Concentration: Finance, Accounting
GMAT Date: 05-28-2013
GPA: 3.6
Followers: 0

Kudos [?]: 11 [0], given: 20

Re: Robots X, Y, and Z each assemble components at their [#permalink]  07 May 2013, 13:10
laythesmack23 wrote:
Does this equation work when plugging in numbers, opposed to looking at pure variables?

Sure. Lets say the rates are X = 5, Y = 6 and Z = 7.

Y/Z = 6/7 -> as stated in II

X/Y = 5/6 and Y/Z = 6/7 -> 5/6< 6/7 as stated in I

Cheers
_________________

........................................................................................
See it big and keep it simple.

Intern
Joined: 01 Jul 2013
Posts: 19
Schools: LBS MIF '15
Followers: 0

Kudos [?]: 38 [0], given: 16

Re: Robots X, Y, and Z each assemble [#permalink]  22 Oct 2013, 07:00
Bunuel wrote:
Robots X, Y, and Z each assemble components at their respective constant rates. If r(x) is the ratio of robot X's constant rate to robot Z's constant rate and r(y) is the ratio of robot Y's constant rate to robot Z's constant rate, is robot Z's constant rate the greatest of the three?

Let the rates of robots X, Y, and Z be x, y, and z respectively. Given: $$r_x=\frac{x}{z}$$ and $$r_y=\frac{y}{z}$$. Question is $$z>x$$ and $$z>y$$?

(1) $$r_x<r_y$$ --> $$\frac{x}{z}<\frac{y}{z}$$ --> $$x<y$$. Not sufficient.

(2) $$r_y<1$$ --> $$\frac{y}{z}<1$$ --> $$y<z$$. Not sufficient.

(1)+(2) As $$x<y$$ and $$y<z$$ then $$x<y<z$$. Sufficient.

Bunuel,

Please help me clarify. The question says "Robots X, Y, and Z each assemble components at their respective constant rates. If r(x) is the ratio of robot X's constant rate to robot Z's constant rate", so if it is rates, why is X's constant rate not 1/X (which is the rate of completing one unit of work, and Z's rate would therefore be 1/Z. Thus r(x) would be 1/X : 1/Z? What am I misunderstanding here?
Math Expert
Joined: 02 Sep 2009
Posts: 28323
Followers: 4482

Kudos [?]: 45338 [0], given: 6752

Re: Robots X, Y, and Z each assemble [#permalink]  22 Oct 2013, 08:22
Expert's post
bulletpoint wrote:
Bunuel wrote:
Robots X, Y, and Z each assemble components at their respective constant rates. If r(x) is the ratio of robot X's constant rate to robot Z's constant rate and r(y) is the ratio of robot Y's constant rate to robot Z's constant rate, is robot Z's constant rate the greatest of the three?

Let the rates of robots X, Y, and Z be x, y, and z respectively. Given: $$r_x=\frac{x}{z}$$ and $$r_y=\frac{y}{z}$$. Question is $$z>x$$ and $$z>y$$?

(1) $$r_x<r_y$$ --> $$\frac{x}{z}<\frac{y}{z}$$ --> $$x<y$$. Not sufficient.

(2) $$r_y<1$$ --> $$\frac{y}{z}<1$$ --> $$y<z$$. Not sufficient.

(1)+(2) As $$x<y$$ and $$y<z$$ then $$x<y<z$$. Sufficient.

Bunuel,

Please help me clarify. The question says "Robots X, Y, and Z each assemble components at their respective constant rates. If r(x) is the ratio of robot X's constant rate to robot Z's constant rate", so if it is rates, why is X's constant rate not 1/X (which is the rate of completing one unit of work, and Z's rate would therefore be 1/Z. Thus r(x) would be 1/X : 1/Z? What am I misunderstanding here?

Because we denoted rates by x , y, and z: let the rates of robots X, Y, and Z be x, y, and z respectively.
_________________
Intern
Joined: 10 Nov 2012
Posts: 30
Followers: 1

Kudos [?]: 16 [0], given: 29

Re: Robots X, Y, and Z each assemble components at their [#permalink]  03 Nov 2013, 07:25
Hello Everyone,
In OG 13, the question uses "rx" and "ry" in the question stem but "r_x (x in suffix)" and "r_y(y in suffix)".
Are these typos?
Or am I supposed to guess that rx and ry of question stem has been converted to r_x and r_y in the two given options?
TIA,
Math Expert
Joined: 02 Sep 2009
Posts: 28323
Followers: 4482

Kudos [?]: 45338 [1] , given: 6752

Re: Robots X, Y, and Z each assemble components at their [#permalink]  03 Nov 2013, 10:21
1
KUDOS
Expert's post
drebellion wrote:
Hello Everyone,
In OG 13, the question uses "rx" and "ry" in the question stem but "r_x (x in suffix)" and "r_y(y in suffix)".
Are these typos?
Or am I supposed to guess that rx and ry of question stem has been converted to r_x and r_y in the two given options?
TIA,

It's a typo. x and y must be indexes in both stem and the statements.
_________________
Intern
Joined: 10 Nov 2012
Posts: 30
Followers: 1

Kudos [?]: 16 [1] , given: 29

Re: Robots X, Y, and Z each assemble components at their [#permalink]  03 Nov 2013, 11:06
1
KUDOS
Also thank you for pointing out the error/typo in Diagnostic Test Q 5 (Cylindrical tank contains 36PI f3 of water...)

At lest for the second question (Cylindrical Tank...) we will never know if its a typo or the guys who had this question in their real GMAT were unfortunate!

Thanks Anyway!
Re: Robots X, Y, and Z each assemble components at their   [#permalink] 03 Nov 2013, 11:06
Similar topics Replies Last post
Similar
Topics:
10 Is |x-z| = |y-z|? 12 05 Jul 2013, 10:54
11 Robots X, Y, and Z each assemble components at their respect 10 24 Sep 2012, 04:16
1 Robots X, Y, and Z each assemble components at their 7 31 Mar 2009, 16:00
Each of the number of w,x,y,z is equal to either 0 or 1. 1 22 Mar 2008, 17:10
Robots X, Y and Z each assemble components at their 2 12 Mar 2006, 12:09
Display posts from previous: Sort by