GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 17 Oct 2019, 13:36

Close

GMAT Club Daily Prep

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.

Close

Request Expert Reply

Confirm Cancel

If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58402
If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0  [#permalink]

Show Tags

New post 29 Dec 2016, 11:56
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

49% (01:44) correct 51% (02:07) wrong based on 109 sessions

HideShow timer Statistics

Senior Manager
Senior Manager
User avatar
S
Joined: 24 Oct 2016
Posts: 251
Location: India
Concentration: Finance, International Business
Schools: IIMB
GMAT 1: 550 Q42 V28
GPA: 3.96
WE: Human Resources (Retail Banking)
Re: If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0  [#permalink]

Show Tags

New post 29 Dec 2016, 12:21
as it is clear that none of these(abcd)can't be zero.so,
st.1 we may have two cases
1. -2<-1<1, always abcd>0
2. 2<3<4, always abcd>0 hence suff.
st.2 whatever values we take for bcd one has to be -ve, say b is -ve then a must has to be -ve and product of abcd>0 always. or we can take values of bcd -ve then a must has to be -ve , hence abcd>0 so suff.

thanks.
regards
nks2611
Current Student
avatar
B
Joined: 25 Dec 2016
Posts: 20
Location: India
GMAT 1: 760 Q51 V41
Re: If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0  [#permalink]

Show Tags

New post 30 Dec 2016, 01:24
Statement 1, abc>0, the possible cases are
i) a, b <0 and c>0, which means d>0.
ii) a, b, c >0, which means d>0.
And in both cases, abcd>0.

Statement 2, bcd<0, the possible cases are
i) b <0 and c, d>0, which means a<0.
ii) b, c, d <0, which means a<0.
And in both cases, abcd>0.

D
SVP
SVP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1685
Location: India
Concentration: International Business, Operations
Schools: INSEAD Jan '19
GPA: 3.01
WE: Engineering (Real Estate)
Reviews Badge CAT Tests
Re: If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0  [#permalink]

Show Tags

New post 30 Dec 2016, 06:33
1
Bunuel wrote:
If a < b < c < d, is abcd > 0?

(1) abc > 0
(2) bcd < 0


Question: If a < b < c < d, is a*b*c*d > 0?

Answer to the question is YES if all variables are +ve or all variables are -ve or only two variables are +ve or -ve.

As per statement-1

a*b*c > 0, this can happen in two cases when all the variables are +ve or two variables are -ve.

So if a = 1, b =2 and c = 3 then d has to be greater than 3 as per question

or if a = -2 , b = -1 and c = 1 then d has to be greater than 2 (no variable in our case can be equal to "0").

In both the cases answer to our question is YES a*b*c*d > 0

So sufficient

As per statement-2

b*c*d < 0 , this can happen in two cases when all variables are -ve or only one variable is -ve.

If b = -1, c = 1, d = 2 then a has to be less than -1, So answer to the question is YES a*b*c*d > 0

If b = -3, c = -2, d = -1 then a has to be less than -3, Again answer to the question is YES a*b*c*d > 0

So sufficient.

(D)
_________________
"Do not watch clock; Do what it does. KEEP GOING."
Current Student
User avatar
S
Status: Preparing for GMAT!!
Joined: 11 Oct 2015
Posts: 126
Location: India
Concentration: Entrepreneurship, International Business
GMAT 1: 660 Q47 V34
GMAT 2: 700 Q48 V38
GPA: 3.1
WE: General Management (Entertainment and Sports)
GMAT ToolKit User
Re: If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0  [#permalink]

Show Tags

New post 30 Dec 2016, 15:23
Bunuel wrote:
If a < b < c < d, is abcd > 0?

(1) abc > 0
(2) bcd < 0

1) abc>0 .. we already know that d is the greatest. Yes. So sufficient.
2) bcd<0 .. we already know that a is the least. No. So sufficient.

D.

Sent from my SM-G935F using GMAT Club Forum mobile app
_________________
Yours,
Siva Rama Krishna Meka :)
Senior Manager
Senior Manager
avatar
G
Status: Countdown Begins...
Joined: 03 Jul 2016
Posts: 277
Location: India
Concentration: Technology, Strategy
Schools: IIMB
GMAT 1: 580 Q48 V22
GPA: 3.7
WE: Information Technology (Consulting)
GMAT ToolKit User Reviews Badge
Re: If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0  [#permalink]

Show Tags

New post 30 Dec 2016, 21:28
IMO D.

abc> 0 implies, either all of them are greater than 0 or only two of them are < 0 which would be a and b. Thus d would be positive. hence abcd>0. Suff
bcd<0 implies either all of them are less than 0 that also means a<0 -- abcd>0 or only one of them is <0 which would be b. and so a also should be less than 0. -- abcd>0. Suff.
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13244
Re: If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0  [#permalink]

Show Tags

New post 27 Feb 2018, 09:55
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 Club Bot
Re: If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0   [#permalink] 27 Feb 2018, 09:55
Display posts from previous: Sort by

If a < b < c < d, is abcd > 0? (1) abc > 0 (2) bcd < 0

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne