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

 It is currently 17 Jul 2018, 21:53

### 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

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

# Is zp negative?

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 47047

### Show Tags

25 Oct 2015, 09:13
3
17
00:00

Difficulty:

35% (medium)

Question Stats:

71% (01:14) correct 29% (01:02) wrong based on 1218 sessions

### HideShow timer Statistics

Is zp negative?

(1) pz^4 < 0
(2) p + z^4 = 14

Kudos for a correct solution.

_________________
SVP
Joined: 08 Jul 2010
Posts: 2119
Location: India
GMAT: INSIGHT
WE: Education (Education)

### Show Tags

26 Oct 2015, 06:14
5
1
Bunuel wrote:
Is zp negative?

(1) pz^4 < 0
(2) p + z^4 = 14

Kudos for a correct solution.

Question : Is zp negative?

Statement 1: pz^4 < 0
i.e. p is Negative because z^4 must be positive for given Inequation
But since the sign of z is still unknown hence,
NOT SUFFICIENT

Statement 2: p + z^4 = 14
As per this inequation p and z can have any sign positive or negative hence nothing can be concluded
NOT SUFFICIENT

Combining the two statements
p is Negative but even after combining the two statement we can't conclude the sign of z. Hence,
NOT SUFFICIENT

_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

##### General Discussion
Current Student
Joined: 20 Mar 2014
Posts: 2641
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)

### Show Tags

25 Oct 2015, 09:47
Bunuel wrote:
Is zp negative?

(1) pz^4 < 0
(2) p + z^4 = 14

Kudos for a correct solution.

zp<0 ?

Per statement 1, pz^4<0 ---> not sufficient, p=-1, z=4 or p=-1, z=-4.

Per statement 2, p + z^4 = 14 ---> p=13, z=-1 gives you a "yes" but p=3, z^4 = 11, not sufficient,

Combining, you still can not eliminate the cases raised above, making E the correct answer.
Manager
Joined: 11 Sep 2013
Posts: 110

### Show Tags

25 Oct 2015, 09:49
2
Bunuel wrote:
Is zp negative?

(1) pz^4 < 0
(2) p + z^4 = 14

Kudos for a correct solution.

(1) pz^4 < 0
=> p<0 but we do not know the sign of z
=> Do not know the sign of pz
=> Insufficient
(2) p + z^4 = 14
We do not know the sign of both p and z
=> Insufficient
(1) + (2): insufficient

Ans: E
Intern
Joined: 02 Jan 2014
Posts: 39

### Show Tags

26 Oct 2015, 01:28
2
1

Explaination:- Question asks, Is zp <0 ?

Considering statement (1) pz^4 < 0 , as z has even power we cannot say anything about whether z is + or -. It follows BCE.

Now consider statement (2) p + z^4 = 14, => p=14-z^4, now this leads us to options p can be + or negative based on z's values.
For example, p=14-16 is -2 and p=14-1^4 is 13.

Even combining both of them does not provide any solution so I go for option E.
Manager
Joined: 22 Feb 2015
Posts: 56
Location: United States
Concentration: Finance, Operations
GMAT Date: 04-01-2015
GPA: 3.98

### Show Tags

26 Oct 2015, 04:57
4
Is zp negative?

(1) pz^4 < 0
(2) p + z^4 = 14

Sol. zp is negative when either z or p is negative
1) pz^4 <0 so z^4 is always +ve sp p is -ve but we dont know anything about z so insufficient
2) p + z^4 = 14 Dont know anything about p and z so insufficient

1) + 2) p(14-p) <0 either p <0 or 14 - p <0 or p >14 so noot sufficient

E must be the correct answer
_________________

Click +1 KUDOS , You can make me happy with just one click! Thanks

Manager
Joined: 13 Feb 2011
Posts: 93

### Show Tags

26 Dec 2015, 19:00
1
In order for $$zp<0$$, only one out of z and p must be negative and not both.

Statement 1 tells that $$p<0$$ but nothing about z (as $$z^4$$ will always be positive whether z is positive or negative). Hence, insufficient.
Statement 2 doesn't tells anything about the signs of p and z as they could be either positive or negative to get a sum of 14. Hence, insufficient.

Combining both statements, we know that $$p<0$$ and $$p+z^4=14$$, that only helps us to conclude that $$z^4>14$$, which again doesn't helps in confirming the sign of z (i.e. whether it's positive or negative). Hence, insufficient.

Hope it helps.
Intern
Joined: 18 Jan 2017
Posts: 36

### Show Tags

21 Jan 2017, 10:27
The main issue is that even with both the statements, we still don't know the sign of "z". It can be either positive or negative. Hence, we cannot say for sure whether zp <0.
Senior Manager
Joined: 05 Dec 2016
Posts: 259
Concentration: Strategy, Finance
GMAT 1: 620 Q46 V29

### Show Tags

16 Feb 2017, 04:00
Playing around with different signs of z we get different signs of pz, thus E.
CEO
Joined: 12 Sep 2015
Posts: 2633

### Show Tags

03 Aug 2017, 14:12
Top Contributor
Bunuel wrote:
Is zp negative?

(1) pz^4 < 0
(2) p + z^4 = 14

Kudos for a correct solution.

Target question: Is zp negative?

Statement 1: p(z^4) < 0
This statement doesn't FEEL sufficient, so I'll TEST some values.
There are several values of p and z that satisfy statement 1. Here are two:
Case a: p = -1 and z = 1. In this case, pz = (-1)(1) = -1. So, pz IS negative.
Case b: p = -1 and z = -1. In this case, pz = (-1)(-1) = 1. So, pz is NOT negative.
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: p + (z^4) = 14
There are several values of p and z that satisfy statement 1. Here are two:
Case a: p = -2 and z = 2. In this case, pz = (-2)(2) = -4. So, pz IS negative.
Case b: p = -2 and z = -2. In this case, pz = (-2)(-2) = 4. So, pz is NOT negative.
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
There are still several values of p and z that satisfy BOTH statements. Here are two:
Case a: p = -2 and z = 2. In this case, pz = (-2)(2) = -4. So, pz IS negative.
Case b: p = -2 and z = -2. In this case, pz = (-2)(-2) = 4. So, pz is NOT negative.
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

_________________

Brent Hanneson – Founder of gmatprepnow.com

Senior Manager
Joined: 16 Nov 2016
Posts: 252

### Show Tags

09 Jul 2018, 23:14
Hi,

I don't have a copy of og16,

will someone confirm whether in statement 1. only p is raised to 4 or zp is raised to 4?
it looks ambiguous...i assumed it is only z^4 and got it right
_________________

If you find my post useful, please give me a kudos.

Thank you.
Regards,
ENEM

If you wish to spend wisely on your gmat prep material, check my post titled: How to Spend Money On GMAT Material Wisely, link: https://gmatclub.com/forum/how-to-buy-gmat-material-wisely-tag-free-gmat-resources-236174.html

Simple and handy template for CR: https://gmatclub.com/forum/simple-and-handy-template-for-cr-242255.html

simple template for more vs greater and fewer vs less: https://gmatclub.com/forum/simple-template-for-more-vs-greater-and-fewer-vs-less-242216.html

Math Expert
Joined: 02 Sep 2009
Posts: 47047

### Show Tags

09 Jul 2018, 23:45
1
ENEM wrote:
Hi,

I don't have a copy of og16,

will someone confirm whether in statement 1. only p is raised to 4 or zp is raised to 4?
it looks ambiguous...i assumed it is only z^4 and got it right

If pz were raised to the power it would be written (pz)^4. Since it's written pz^4, then only z is raised to the power.
_________________
Re: Is zp negative?   [#permalink] 09 Jul 2018, 23:45
Display posts from previous: Sort by

# Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.