Oct 20 07:00 AM PDT  09:00 AM PDT Get personalized insights on how to achieve your Target Quant Score. Oct 22 08:00 PM PDT  09:00 PM PDT On Demand for $79. For a score of 4951 (from current actual score of 40+) AllInOne Standard & 700+ Level Questions (150 questions) Oct 23 08:00 AM PDT  09:00 AM PDT Join an exclusive interview with the people behind the test. If you're taking the GMAT, this is a webinar you cannot afford to miss! Oct 26 07:00 AM PDT  09:00 AM PDT Want to score 90 percentile or higher on GMAT CR? Attend this free webinar to learn how to prethink assumptions and solve the most challenging questions in less than 2 minutes.
Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 12 Nov 2011
Posts: 59

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:
85% (01:22) correct 15% (01:33) wrong based on 312 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: 209
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: 58443

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.
_________________



Manager
Joined: 01 Nov 2010
Posts: 209
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: 59

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: 46

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: 128

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: 445
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: 58443

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.
_________________



Intern
Joined: 23 Aug 2014
Posts: 31
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: 58443

Re: a, b, c, and d are integers; abcd ≠ 0; what is the value of cd?
[#permalink]
Show Tags
10 Nov 2014, 11:53
deeuk wrote: Bunuel, I think there is a typo the option (c) i.e, (1)+(2) is 'sufficient', right? Right. Edited. Thank you.
_________________



Current Student
Status: DONE!
Joined: 05 Sep 2016
Posts: 357

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






