Mar 23 07:00 AM PDT  09:00 AM PDT Christina scored 760 by having clear (ability) milestones and a trackable plan to achieve the same. Attend this webinar to learn how to build trackable milestones that leverage your strengths to help you get to your target GMAT score. Mar 27 03:00 PM PDT  04:00 PM PDT Join a free live webinar and learn the winning strategy for a 700+ score on GMAT & the perfect application. Save your spot today! Wednesday, March 27th at 3 pm PST Mar 29 10:00 PM PDT  11:00 PM PDT Right now, their GMAT prep, GRE prep, and MBA admissions consulting services are up to $1,100 off. GMAT (Save up to $261): SPRINGEXTRAGMAT GRE Prep (Save up to $149): SPRINGEXTRAGRE MBA (Save up to $1,240): SPRINGEXTRAMBA Mar 30 07:00 AM PDT  09:00 AM PDT Attend this webinar and master GMAT SC in 10 days by learning how meaning and logic can help you tackle 700+ level SC questions with ease.
Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 12 Nov 2011
Posts: 70

a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
16 Jan 2012, 00:43
Question Stats:
84% (01:24) correct 16% (01:32) wrong based on 290 sessions
HideShow timer Statistics
a, b, c, and d are integers; abcd ≠ 0; what is the value of cd? (1) \(\frac{c}{b} = \frac{2}{d}\) (2) \(b^3*a^4*c = 27*a^4*c\)
Official Answer and Stats are available only to registered users. Register/ Login.



Manager
Joined: 01 Nov 2010
Posts: 221
Location: India
Concentration: Technology, Marketing
GMAT Date: 08272012
GPA: 3.8
WE: Marketing (Manufacturing)

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
Updated on: 16 Jan 2012, 03:30
a, b, c, and d are integers; abcd >< 0; what is the value of cd? 1) c/b = 2/d 2) b^3*a^4*c = 27*a^4*c SOLUTION: statement 1: c/b = 2/d cd = 2b, we don't know the value of b. so. we can't find the value of cd. NOT SUFFICIENT statement 2 : b^3*a^4*c = 27*a^4*c ==> a^4 * c (b^327) = 0 it means, a^4 =0 or c =0 or b^3 =27 so, b = 3 so, here we can get different values of cd. NOT SUFFICIENT after combining both statement , we can get value of cd = 2b =6 Hence the ans is C. I HOPE IT WILL BE HELPFUL. PS: EDITED after bunuel explanation
_________________
kudos me if you like my post.
Attitude determine everything. all the best and God bless you.



Math Expert
Joined: 02 Sep 2009
Posts: 53792

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
16 Jan 2012, 03:11
a, b, c, and d are integers; abcd≠0; what is the value of cd?(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Not sufficient. (2) b^3*a^4*c = 27*a^4*c > as \(a\) and \(c\) does not equal to zero we can safely reduce both parts by \(a^4*c\) > \(b^3=27\) > \(b=3\). Not sufficient. (1)+(2) As from (1) \(cd=2b\) and from (2) \(b=3\) then \(cd=2b=6\). Sufficient. Answer:C. As for your question: Runner2 wrote: 2  clearly not suff, and we got that b^3=27 cause what if c negative? so we can't say for sure that b=3 like stated in OA. Am I right? Odd roots have the same sign as the base of the root. For example, \(\sqrt[3]{125} =5\) and \(\sqrt[3]{64} =4\). So \(\sqrt[3]{27}=3\) and not \(3\) > \(3^3=27\) and \((3)^3=27\). Hope its' 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



Manager
Joined: 01 Nov 2010
Posts: 221
Location: India
Concentration: Technology, Marketing
GMAT Date: 08272012
GPA: 3.8
WE: Marketing (Manufacturing)

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
16 Jan 2012, 03:33
@bunuel thanks for explanation. it looks that my mind was somewhere else while solving the question. many times i misses an obvious point , main reason never to the 51 in Quant. i will have to focus more. anyway, i have edited my explanation.
_________________
kudos me if you like my post.
Attitude determine everything. all the best and God bless you.



Manager
Joined: 12 Nov 2011
Posts: 70

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
16 Jan 2012, 04:19
thanks for explanation, you should agree very stupid and easy question, I should sleep more not to make such mistakes....



Intern
Joined: 03 Oct 2009
Posts: 49

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
21 Jan 2012, 14:45
a, b, c, and d are integers; abcd >< 0; what is the value of cd?
1) c/b = 2/d
c = (2*b)/(d) not sufficient
2) b^3*a^4*c = 27*a^4*c
b^3 = 27 b = 3
not sufficient.
1 + 2
c = (2*3)/d c = (6)/d cd = 6
sufficient.
sufficient.



Manager
Status: Bunuel's fan!
Joined: 08 Jul 2011
Posts: 151

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
17 May 2012, 09:22
Bunuel wrote: a, b, c, and d are integers; abcd≠0; what is the value of cd?
(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Sufficient. . Bunuel, i think what you meant here is Not Sufficient. Correct?



Senior Manager
Joined: 24 Aug 2009
Posts: 464
Schools: Harvard, Columbia, Stern, Booth, LSB,

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
13 Sep 2012, 08:12
Bunuel wrote: a, b, c, and d are integers; abcd≠0; what is the value of cd?(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Sufficient. (2) b^3*a^4*c = 27*a^4*c > as \(a\) and \(c\) does not equal to zero we can safely reduce both parts by \(a^4*c\) > \(b^3=27\) > \(b=3\). Not sufficient. (1)+(2) As from (1) \(cd=2b\) and from (2) \(b=3\) then \(cd=2b=6\). Not sufficient. Answer:C. As for your question: Runner2 wrote: 2  clearly not suff, and we got that b^3=27 cause what if c negative? so we can't say for sure that b=3 like stated in OA. Am I right? Odd roots have the same sign as the base of the root. For example, \(\sqrt[3]{125} =5\) and \(\sqrt[3]{64} =4\). So \(\sqrt[3]{27}=3\) and not \(3\) > \(3^3=27\) and \((3)^3=27\). Hope its' clear. Hi Bunuel, There is a slight typing error in the explanation. Statement "(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Sufficient." should read "(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Insufficient." Correct me if i am wrong.
_________________
If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS. Kudos always maximizes GMATCLUB worth Game Theory
If you have any question regarding my post, kindly pm me or else I won't be able to reply



Math Expert
Joined: 02 Sep 2009
Posts: 53792

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
13 Sep 2012, 08:18
fameatop wrote: Bunuel wrote: a, b, c, and d are integers; abcd≠0; what is the value of cd?(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Sufficient. (2) b^3*a^4*c = 27*a^4*c > as \(a\) and \(c\) does not equal to zero we can safely reduce both parts by \(a^4*c\) > \(b^3=27\) > \(b=3\). Not sufficient. (1)+(2) As from (1) \(cd=2b\) and from (2) \(b=3\) then \(cd=2b=6\). Not sufficient. Answer:C. As for your question: Runner2 wrote: 2  clearly not suff, and we got that b^3=27 cause what if c negative? so we can't say for sure that b=3 like stated in OA. Am I right? Odd roots have the same sign as the base of the root. For example, \(\sqrt[3]{125} =5\) and \(\sqrt[3]{64} =4\). So \(\sqrt[3]{27}=3\) and not \(3\) > \(3^3=27\) and \((3)^3=27\). Hope its' clear. Hi Bunuel, There is a slight typing error in the explanation. Statement "(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Sufficient." should read "(1) c/b = 2/d > \(cd=2b\), we don't know the value of \(b\) to get the single numerical value of \(cd\). Insufficient." Correct me if i am wrong. Thank you. Typo edited.
_________________
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: 23 Aug 2014
Posts: 34
GMAT Date: 11292014

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
10 Nov 2014, 11:46
Bunuel, I think there is a typo the option (c) i.e, (1)+(2) is 'sufficient', right?



Math Expert
Joined: 02 Sep 2009
Posts: 53792

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
10 Nov 2014, 11:53



Current Student
Status: DONE!
Joined: 05 Sep 2016
Posts: 372

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
16 Sep 2016, 17:37
D is correct. Here's why:
(1) x^(2) yz = 12xy > xz = 12
SUFFICIENT
(2) (z/4)  (3/x) > xz = 12
SUFFICIENT



Intern
Joined: 19 Aug 2017
Posts: 11

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
12 Jan 2019, 10:19
law258, that looks like a different problem from the one in this post.
_________________
GMAT Tutor  MBA Prep Tutoring https://mbapreptutoring.com/
Free resources: Probabilities Seminar  Error_Log  Ultimate guide to understand the GMAT Algorithm




Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
12 Jan 2019, 10:19






