November 14, 2018 November 14, 2018 07:00 PM PST 08:00 PM PST Join the webinar and learn timemanagement tactics that will guarantee you answer all questions, in all sections, on time. Save your spot today! Nov. 14th at 7 PM PST November 15, 2018 November 15, 2018 10:00 PM MST 11:00 PM MST EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299)
Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 12 Sep 2010
Posts: 9

Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
18 Sep 2010, 20:13
Question Stats:
62% (02:04) correct 38% (01:58) wrong based on 547 sessions
HideShow timer Statistics
Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone? (1) Machines X and Y, working together, fill a production order of this size in twothirds the time that machine X, working alone, does (2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does Can you explain this one Bunuel plz? At the end,we are having a definite quantity "X"..Right?So I still feel the answer is D. Because there is no other value/variable affecting the outcome except for the "X".Please clarify if I am going badly wrong somewhere! Attachment:
DS3 (1).jpg [ 143.42 KiB  Viewed 6783 times ]
Official Answer and Stats are available only to registered users. Register/ Login.




Math Expert
Joined: 02 Sep 2009
Posts: 50572

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
18 Sep 2010, 20:31
Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size. Question: \(yx=?\) (1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient (2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient (1)+(2) Nothing new. Not Sufficient. Answer: E. Hope it helps. P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
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? Extrahard Quant Tests with Brilliant Analytics




Manager
Joined: 23 Sep 2009
Posts: 123

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
19 Sep 2010, 16:52
Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Pardon me if this is a stupid approach. but still I want to get it clarified. From 1, as you said, \frac{1}{x}+\frac{1}{y}=\frac{2x}{3} threfore \frac{1}{y}=\frac{2x}{3}\frac{1}{x} this gives \frac{1}{y}=\frac{2x^23}{3x} Now using the value y=2x, substitute in the above equation and u get 2x^2=\frac{9}{4} hence x=\frac{3}{2} with this we can even find y. Hence answer is C. What is wrong in this approach?
_________________
Thanks, VP



Math Expert
Joined: 02 Sep 2009
Posts: 50572

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
19 Sep 2010, 22:26
vigneshpandi wrote: Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Pardon me if this is a stupid approach. but still I want to get it clarified. From 1, as you said, ...\(\frac{1}{x}+\frac{1}{y}=\frac{2x}{3}\) threfore \(\frac{1}{y}=\frac{2x}{3}\frac{1}{x}\) this gives \(\frac{1}{y}=\frac{2x^23}{3x}\) Now using the value y=2x, substitute in the above equation and u get 2x^2=\frac{9}{4} hence x=\frac{3}{2}with this we can even find y. Hence answer is C. What is wrong in this approach? What you are basically saying is that you can solve 1 equation \(\frac{xy}{x+y}=x*\frac{2}{3}\) with 2 unknowns \(x\) and \(y\). Though it's not generally impossible (for example: 2x+y=y+4) this is not the case here. Next, we have \(total \ time=\frac{xy}{x+y}=x*\frac{2}{3}\) and not \(\frac{1}{x}+\frac{1}{y}=\frac{2x}{3}\) as you wrote (the calculation in red is not correct, it should be: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}=\frac{1}{x*\frac{2}{3}}=\frac{3}{2x}\)). So if you substitute \(y\) by \(2x\) in \(total \ time=\frac{xy}{x+y}=x*\frac{2}{3}\) (which by the way gives this relationship) you don't get the \(x=\frac{3}{2}\), you'll get \(x*\frac{2}{3}=x*\frac{2}{3}\) > \(\frac{2}{3}=\frac{2}{3}\) as \(x\) will cancel out. Hope it's clear.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
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? Extrahard Quant Tests with Brilliant Analytics



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8527
Location: Pune, India

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
30 Nov 2010, 09:14
In this question, I would like to discuss the use of logic. Ques: How many more hours does it take machine Y than it does machine X. So I am looking for a number like 2 hrs or something. Neither of the statements gives me a number of hours for anything. Only relative time taken. So we can straight away say the answer is (E). Also, how to deal with a statement like without getting into equations and variables: Machines X and Y, working together, fill an order in 2/3 the time that machine X, working alone, does. Together, they take 2/3 the time taken by machine X. i.e. if machine X took 6 hrs, together they took 4 hrs. The 2 hrs were saved because machine Y was also working for those 4 hrs. In 4 hrs machine Y did what machine X would have done in 2 hrs. So time taken by machine Y alone will be twice the time taken by machine X alone.
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
GMAT selfstudy has never been more personalized or more fun. Try ORION Free!



Senior Manager
Joined: 07 Apr 2012
Posts: 370

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
03 Nov 2013, 14:07
Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Hi Bunuel, Can you please see why my logic is not correct? my equation was this: (X+Y)*2*(Z/3) = XZ where X is the rate of machine X, Y the rate of machine Y and Z is the time it takes for machine X to fill the order alone. In the end, I get an equation that is opposite from what you got: 2Y=X. What's wrong with that?



Math Expert
Joined: 02 Sep 2009
Posts: 50572

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
04 Nov 2013, 00:53
ronr34 wrote: Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Hi Bunuel, Can you please see why my logic is not correct? my equation was this: (X+Y)*2*(Z/3) = XZ where X is the rate of machine X, Y the rate of machine Y and Z is the time it takes for machine X to fill the order alone. In the end, I get an equation that is opposite from what you got: 2Y=X. What's wrong with that? Please read solutions carefully.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
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? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 11 Nov 2013
Posts: 16
GMAT Date: 12262013
GPA: 3.6
WE: Consulting (Computer Software)

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
04 Dec 2013, 11:15
Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Hi, I am not understanding statement 1. If x & Y are the rates respectively , then 1/X and 1/Y are the time taken to complete the task. Shouldnt the equation be 1/X + 1/Y = 2/3X It gives a degree 3 equation but I am not sure where I am going wrong in logic ?



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 8527
Location: Pune, India

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
04 Dec 2013, 20:27
A4G wrote: Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Hi, I am not understanding statement 1. If x & Y are the rates respectively , then 1/X and 1/Y are the time taken to complete the task. Shouldnt the equation be 1/X + 1/Y = 2/3X It gives a degree 3 equation but I am not sure where I am going wrong in logic ? As Bunuel noted above, X is the time taken by machine X and Y is the time taken by machine Y. Combined time taken is 2X/3 Rates are 1/X and 1/Y which are additive. The combined rate is 3/2X 1/X + 1/Y = 3/2X Also note that you are trying to add individual time taken in your equation. But times are not additive, only rates are additive. e.g. if you take 2 hrs to complete a work and I take 3 hrs, together will we take 5 hrs? I hope you understand that we will take less than 2 hrs for sure because you alone can complete it in 2 hrs. So times are NOT additive.
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
GMAT selfstudy has never been more personalized or more fun. Try ORION Free!



Intern
Joined: 11 Nov 2013
Posts: 16
GMAT Date: 12262013
GPA: 3.6
WE: Consulting (Computer Software)

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
04 Dec 2013, 22:07
VeritasPrepKarishma wrote: A4G wrote: Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Hi, I am not understanding statement 1. If x & Y are the rates respectively , then 1/X and 1/Y are the time taken to complete the task. Shouldnt the equation be 1/X + 1/Y = 2/3X It gives a degree 3 equation but I am not sure where I am going wrong in logic ? As Bunuel noted above, X is the time taken by machine X and Y is the time taken by machine Y. Combined time taken is 2X/3 Rates are 1/X and 1/Y which are additive. The combined rate is 3/2X 1/X + 1/Y = 3/2X Also note that you are trying to add individual time taken in your equation. But times are not additive, only rates are additive. e.g. if you take 2 hrs to complete a work and I take 3 hrs, together will we take 5 hrs? I hope you understand that we will take less than 2 hrs for sure because you alone can complete it in 2 hrs. So times are NOT additive. Thanks Karishma .. The point you made about time really makes sense and I missed a small but very important point



Manager
Joined: 28 Apr 2014
Posts: 224

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
04 May 2014, 23:29
Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Bunuel my thought process was that  No where in the question is the absolute time mentioned for any any machine so none of the 2 points are sufficent . hence E.



Math Expert
Joined: 02 Sep 2009
Posts: 50572

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
05 May 2014, 00:36
himanshujovi wrote: Bunuel wrote: Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
Let \(x\) and \(y\) be the times needed for machines X and Y respectively working alone to fill a production order of this size.
Question: \(yx=?\)
(1) Machines X and Y, working together, fill a production order of this size in 2/3 the time that machine X, working alone, does > general relationship: \(\frac{1}{x}+\frac{1}{y}=\frac{1}{total \ time}\) > Total time needed for machines X and Y working together is \(total \ time=\frac{xy}{x+y}\) (general formula) > given \(\frac{xy}{x+y}=x*\frac{2}{3}\) > \(2x=y\). Not sufficient
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does > \(2x=y\), the same info. Not sufficient
(1)+(2) Nothing new. Not Sufficient.
Answer: E.
Hope it helps.
P.S. Please post one question per topic. Also you can attach image files directly so no need to attach zip files. Bunuel my thought process was that  No where in the question is the absolute time mentioned for any any machine so none of the 2 points are sufficent . hence E. That's not entirely correct. For example, if the first statement were: machines X and Y, working together, fill a production order of this size in 1/2 the time that machine X, working alone, does, then this would be sufficient. Because in this case we would have x=y, and hence xy=0. Does this make sense?
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
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? Extrahard Quant Tests with Brilliant Analytics



NonHuman User
Joined: 09 Sep 2013
Posts: 8759

Re: Machines X and Y work at their respective constant rates. How many
[#permalink]
Show Tags
06 Feb 2018, 10:36
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.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: Machines X and Y work at their respective constant rates. How many &nbs
[#permalink]
06 Feb 2018, 10:36






