Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 21 Aug 2011
Posts: 20

If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? [#permalink]
Show Tags
24 Aug 2011, 19:04
7
This post was BOOKMARKED
Question Stats:
58% (01:17) correct 43% (01:19) wrong based on 160 sessions
HideShow timer Statistics
If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? (1) r^2=25 (2) r=5
Official Answer and Stats are available only to registered users. Register/ Login.
Last edited by Bunuel on 13 May 2013, 02:20, edited 1 time in total.
Edited the question.



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7960
Location: Pune, India

Re: Help~ [#permalink]
Show Tags
24 Aug 2011, 22:23
2
This post received KUDOS
Expert's post
1
This post was BOOKMARKED
Jasonammex wrote: if (y+3)(y1)(y2)(y1)=r(y1), what is the value of y?
(1) r^2=25 (2) r=5
I chose A... In the equation above we see that (y1) is the common factor in all terms. So let's take (y1) common out of all the terms. (y+3)(y1)  (y2)(y1)  r(y1) = 0 (y1)[(y+3) (y2)  r] = 0 (y1)(5  r) = 0 Now, the product of these two is 0. This means that at least one of them has to be 0. Either (y1) = 0 or (5  r) = 0 or both are 0. So, either y = 1 or r = 5 or both. Only if we know that r is not 5, then we can say that y must be 1. If r is 5, y may be 1 or may not be 1. Stmnt 1: r^2 = 25 So r = + 5 This statement tells us that r can be 5. If r = 5, y may or may not be 1. If r is not 5, y will be 1. Since we do not know whether r is 5 or not, we cannot say what the value of y is. Not sufficient. Stmnt 2: r = 5 If r = 5, y may or may not be 1. Not sufficient. Both together, r = 5. Again, not sufficient. Answer E
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Director
Status: Finally Done. Admitted in Kellogg for 2015 intake
Joined: 25 Jun 2011
Posts: 526
Location: United Kingdom
Concentration: International Business, Strategy
GPA: 2.9
WE: Information Technology (Consulting)

Re: Help~ [#permalink]
Show Tags
26 Aug 2011, 01:49
Correct answer Should be B y1 is the common factor in the question stem Try to break the stem as much as you can So, y1[(y+3)  (y2)] = r(y1) = y+3y+2 = r r=5. So the question becomes is r=5? Statement 1 gives us two solution + and _ 5 So insufficient Statement 2 is sufficient because its same as our new question stem which is r=5. Hope this helps.
_________________
Best Regards, E.
MGMAT 1 > 530 MGMAT 2> 640 MGMAT 3 > 610 GMAT ==> 730



Director
Status: Finally Done. Admitted in Kellogg for 2015 intake
Joined: 25 Jun 2011
Posts: 526
Location: United Kingdom
Concentration: International Business, Strategy
GPA: 2.9
WE: Information Technology (Consulting)

Re: Help~ [#permalink]
Show Tags
26 Aug 2011, 01:50
I am wrong. Sorry guys. Thanks Karishma.
_________________
Best Regards, E.
MGMAT 1 > 530 MGMAT 2> 640 MGMAT 3 > 610 GMAT ==> 730



Intern
Joined: 31 May 2010
Posts: 32
Schools: ESADE, IE

Re: Help~ [#permalink]
Show Tags
26 Aug 2011, 05:05
should be E. The questions becomes y1[y+3  y+2)] = r(y1).
r=5. So, can not calculate the value of Y from both 1 and 2.



Manager
Joined: 29 Jul 2011
Posts: 103
Location: United States

Re: if (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? (1) [#permalink]
Show Tags
07 Jan 2012, 14:31
Rephrasing the stem provides us: (y1)[y+3y+2] = r(y1) (y1)5 = r(y1) (y1)(5r) = 0 y = 1 or r = 5 1. r = +/ 5, if r = 5, y = 1 and if r = 5, y = anything. Insuff. 2. r = 5, which means y = anything. Insuff. Combined, only thing common is r = 5, which still provides y = anything. Insuff. E.
_________________
I am the master of my fate. I am the captain of my soul. Please consider giving +1 Kudos if deserved!
DS  If negative answer only, still sufficient. No need to find exact solution. PS  Always look at the answers first CR  Read the question stem first, hunt for conclusion SC  Meaning first, Grammar second RC  Mentally connect paragraphs as you proceed. Short = 2min, Long = 34 min



Senior Manager
Joined: 25 Feb 2010
Posts: 445

Re: if (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? (1) [#permalink]
Show Tags
13 May 2013, 02:18
Guys I'm bit lost here. (y1)[y+3y+2] = r(y1) (y1)5 = r(y1) (y1) is common here so 5= r which is what stmt 2 tells us. I think i should be B.
_________________
GGG (Gym / GMAT / Girl)  Be Serious
Its your duty to post OA afterwards; some one must be waiting for that...



Math Expert
Joined: 02 Sep 2009
Posts: 43898

Re: if (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? (1) [#permalink]
Show Tags
13 May 2013, 02:30
onedayill wrote: Guys I'm bit lost here.
(y1)[y+3y+2] = r(y1) (y1)5 = r(y1)
(y1) is common here
so 5= r
which is what stmt 2 tells us.
I think i should be B. Notice that we are asked to find the value of y not r. Also, I guess you reduced (y1)5 = r(y1) by y1 which cannot be done here. Never reduce an equation by a variable (or expression with a variable), if you are not certain that the variable (or the expression with a variable) doesn't equal to zero. We can not divide by zero.So, if you divide (reduce) (y1)5 = r(y1) by y1, you assume, with no ground for it, that y1 does not equal to zero thus exclude a possible solution (notice that both y=1 AND r=5 satisfy the equation). Hope it's clear. Complete solution: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y?\((y+3)(y1)  (y2)(y1)  r(y1) = 0\) > \((y1)[(y+3) (y2)  r] = 0\) > \((y1)(5  r) = 0\) > y=1 or/and r=5. (1) r^2=25 > r=5 or r=5. Not sufficient. (2) r=5 > y may or may not be 1. Not sufficient. (1)+(2) The same here: we have that r=5 but y still may or may not be 1. Not sufficient. Answer: E.
_________________
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
Status: Working hard to score better on GMAT
Joined: 02 Oct 2012
Posts: 89
Location: Nepal
Concentration: Finance, Entrepreneurship
GPA: 3.83
WE: Accounting (Consulting)

Re: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? [#permalink]
Show Tags
14 May 2013, 20:21
Hi Buneul, has my logic actually worked here? correct me if i am wrong... Jasonammex wrote: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y?
(1) r^2=25 (2) r=5 From the given statement: (y1)[Y+3y+2]=r(y1) Divide both sides by (y1) y+3y+2=r r=5 Here I thought that in the given statement when Y does not exist it is impossible to calculate the value of Y. Thus both statements are not sufficient. Ans: E
_________________
Do not forget to hit the Kudos button on your left if you find my post helpful.



Math Expert
Joined: 02 Sep 2009
Posts: 43898

Re: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? [#permalink]
Show Tags
15 May 2013, 00:53
atalpanditgmat wrote: Hi Buneul, has my logic actually worked here? correct me if i am wrong... Jasonammex wrote: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y?
(1) r^2=25 (2) r=5 From the given statement: (y1)[Y+3y+2]=r(y1) Divide both sides by (y1) y+3y+2=r r=5 Here I thought that in the given statement when Y does not exist it is impossible to calculate the value of Y. Thus both statements are not sufficient. Ans: E Unfortunately that's not correct. Refer to my post above: ify3y1y2y1ry1whatisthevalueofy119561.html#p1224280Never reduce an equation by a variable (or expression with a variable), if you are not certain that the variable (or the expression with a variable) doesn't equal to zero. We can not divide by zero.So, if you divide (reduce) (y1)5 = r(y1) by y1, you assume, with no ground for it, that y1 does not equal to zero thus exclude a possible solution (notice that both y=1 AND r=5 satisfy the equation).
_________________
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
Status: Working hard to score better on GMAT
Joined: 02 Oct 2012
Posts: 89
Location: Nepal
Concentration: Finance, Entrepreneurship
GPA: 3.83
WE: Accounting (Consulting)

Re: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? [#permalink]
Show Tags
15 May 2013, 20:11
Oops by bad, Thanks Bunuel.
_________________
Do not forget to hit the Kudos button on your left if you find my post helpful.



NonHuman User
Joined: 09 Sep 2013
Posts: 13759

Re: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? [#permalink]
Show Tags
22 May 2016, 08:59
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



Current Student
Joined: 18 Oct 2014
Posts: 902
Location: United States
GPA: 3.98

Re: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? [#permalink]
Show Tags
22 May 2016, 10:41
Jasonammex wrote: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y?
(1) r^2=25 (2) r=5 Given information= (y+3)(y1)(y2)(y1)=r(y1) Question value of y? Inference from given information (y+3)(y1)(y2)(y1)=r(y1) (y+3) (y2)= r (y1) is common at both the sides of the equation. y+3y+2=r r=5 (y is cancelling out at both sides of equation, so most likely we need one of the statement to produce value of y ) (1) r^2=25 It does not give us a solution for y (2) r=5 It does not give us a solution for y E is the answer
_________________
I welcome critical analysis of my post!! That will help me reach 700+



NonHuman User
Joined: 09 Sep 2013
Posts: 13759

Re: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y? [#permalink]
Show Tags
22 May 2017, 19:08
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: If (y+3)(y1)(y2)(y1)=r(y1), what is the value of y?
[#permalink]
22 May 2017, 19:08






