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 Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

brief expl from me 1 - clearly not suff, and we got that cd=2b 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?

Re: a, b, c, and d are integers; abcd≠0 [#permalink]

Show Tags

16 Jan 2012, 02:09

2

This post received KUDOS

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^3-27) = 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.

Last edited by 321kumarsushant on 16 Jan 2012, 03:30, edited 2 times in total.

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 \((-3)^3=-27\).

Re: a, b, c, and d are integers; abcd≠0 [#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.

Re: a, b, c, and d are integers; abcd≠0 [#permalink]

Show Tags

13 Sep 2012, 08:12

1

This post received KUDOS

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

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."

Re: a, b, c, and d are integers; abcd≠0 [#permalink]

Show Tags

02 Feb 2016, 04:49

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.
_________________

After days of waiting, sharing the tension with other applicants in forums, coming up with different theories about invites patterns, and, overall, refreshing my inbox every five minutes to...

I was totally freaking out. Apparently, most of the HBS invites were already sent and I didn’t get one. However, there are still some to come out on...

In early 2012, when I was working as a biomedical researcher at the National Institutes of Health , I decided that I wanted to get an MBA and make the...