 It is currently 25 May 2019, 23:58 ### 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. # a < 0 < b so compare ab and a+b  Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS: GRE Prep Club Legend  Joined: 07 Jun 2014
Posts: 4857
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 112

Kudos [?]: 1865  , given: 397

a < 0 < b so compare ab and a+b [#permalink]
1
This post received
KUDOS
Expert's post 00:00

Question Stats: 57% (00:44) correct 42% (00:41) wrong based on 68 sessions
a < 0 < b

 Quantity A Quantity B ab a+b

A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.

Drill 2
Question: 13
Page: 288
[Reveal] Spoiler: OA

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test GRE Prep Club Legend  Joined: 07 Jun 2014
Posts: 4857
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 112

Kudos [?]: 1865  , given: 397

Re: a < 0 < b so compare ab and a+b [#permalink]
1
This post received
KUDOS
Expert's post
Explanation

Plug in values for a and b. If a = −2 and b = 2, then Quantity B is greater. Eliminate choices A and C. If $$a=\frac{-1}{2}$$ and $$b = \frac{1}{4}$$, then Quantity A is greater. Eliminate choice B.

Hence option D is correct.
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test Intern Joined: 17 Feb 2017
Posts: 11
Followers: 0

Kudos [?]: 5  , given: 18

Re: a < 0 < b so compare ab and a+b [#permalink]
1
This post received
KUDOS
I think the explanation is not properly written. Here it is given that a<0<b, then how can we assume the value of a as 1/2?
if we take a=-1 and b=1, then Column B is greater. Again if we take a=-1 and b=1/2, then both the columns are equal, i.e, Column C
So the answer will be D.
Plz verify if possible GRE Instructor Joined: 10 Apr 2015
Posts: 1795
Followers: 58

Kudos [?]: 1681  , given: 8

Re: a < 0 < b so compare ab and a+b [#permalink]
1
This post received
KUDOS
Expert's post
sandy wrote:
a < 0 < b

 Quantity A Quantity B ab a+b

Given: a < 0 < b
So, a is NEGATIVE and b is POSITIVE

Let's test some values of a and b that satisfy the given information.

Let's first try a = -1 and b = 1
We get:
Quantity A: ab = (-1)(1) = -1
Quantity B: a+b = (-1) + 1 = 0
In this case, Quantity B is greater

Now try a = -2 and b = 0.5
We get:
Quantity A: ab = (-2)(0.5) = -1
Quantity B: a+b = (-2) + 0.5 = -1.5
In this case, Quantity A is greater

Answer: D

RELATED VIDEO

_________________

Brent Hanneson – Creator of greenlighttestprep.com Sign up for my free GRE Question of the Day emails

Manager  Joined: 26 Jun 2017
Posts: 104
Followers: 0

Kudos [?]: 40 , given: 38

Re: a < 0 < b so compare ab and a+b [#permalink]
sandy wrote:
Explanation

Plug in values for a and b. If a = −2 and b = 2, then Quantity B is greater. Eliminate choices A and C. If $$\frac{1}{2}$$ and b = $$\frac{1}{4}$$, then Quantity A is greater. Eliminate choice B.

Hence option D is correct.

please add the minus before 1/2 or revise it not to create confusion
_________________

What you think, you become.

GRE Prep Club Legend  Joined: 07 Jun 2014
Posts: 4857
GRE 1: Q167 V156 WE: Business Development (Energy and Utilities)
Followers: 112

Kudos [?]: 1865 , given: 397

Re: a < 0 < b so compare ab and a+b [#permalink]
Expert's post
boxing506 wrote:
please add the minus before 1/2 or revise it not to create confusion

Fixed! Sorry about the error.
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test Manager Joined: 22 Feb 2018
Posts: 163
Followers: 2

Kudos [?]: 109  , given: 22

Re: a < 0 < b so compare ab and a+b [#permalink]
2
This post received
KUDOS
correct: D
a < 0 < b
for comparing ab and a+b we can't do any simplifications.
we know a is negative and b is positive.Thus, ab is always a negative value. but depending on the value of a and b, a+b can be either positive or negative.
if |a| > |b| : ab is always negative and a+b is negative, so A > B
if |a| <|b| : ab is always negative and a+b is positive, so A < B
if |a| = |b| : ab is always negative and a+b equals zero, so A < B
so based on the relationship between a and b and information, we can't figure out which one is less or more.
the correct answer is D.

_________________

Follow your heart

Intern Joined: 28 Feb 2018
Posts: 30
Followers: 0

Kudos [?]: 2 , given: 0

Re: a < 0 < b so compare ab and a+b [#permalink]
D is correct
Intern Joined: 13 Nov 2018
Posts: 11
Followers: 0

Kudos [?]: 3 , given: 7

Re: a < 0 < b so compare ab and a+b [#permalink]
FatemehAsgarinejad wrote:
correct: D
a < 0 < b
[b]for comparing ab and a+b we can't do any simplifications.

we know a is negative and b is positive.Thus, ab is always a negative value. but depending on the value of a and b, a+b can be either positive or negative.
if |a| > |b| : ab is always negative and a+b is negative, so A > B
if |a| <|b| : ab is always negative and a+b is positive, so A < B
if |a| = |b| : ab is always negative and a+b equals zero, so A < B
so based on the relationship between a and b and information, we can't figure out which one is less or more.
the correct answer is D.[/b]

Hi,

Fatima, refering to the highlighted part. I think we can simplify QTY A & B since B>0. We can divide b on both sides. It's a quesiton. I simplified it to get the answer b.
Intern Joined: 13 Nov 2018
Posts: 11
Followers: 0

Kudos [?]: 3 , given: 7

Re: a < 0 < b so compare ab and a+b [#permalink]
*sorry answer "d"
Manager Joined: 22 Feb 2018
Posts: 163
Followers: 2

Kudos [?]: 109 , given: 22

Re: a < 0 < b so compare ab and a+b [#permalink]
asfandiar wrote:
FatemehAsgarinejad wrote:
correct: D
a < 0 < b
[b]for comparing ab and a+b we can't do any simplifications.

we know a is negative and b is positive.Thus, ab is always a negative value. but depending on the value of a and b, a+b can be either positive or negative.
if |a| > |b| : ab is always negative and a+b is negative, so A > B
if |a| <|b| : ab is always negative and a+b is positive, so A < B
if |a| = |b| : ab is always negative and a+b equals zero, so A < B
so based on the relationship between a and b and information, we can't figure out which one is less or more.
the correct answer is D.[/b]

Hi,

Fatima, refering to the highlighted part. I think we can simplify QTY A & B since B>0. We can divide b on both sides. It's a quesiton. I simplified it to get the answer b.

Hello,
By simplification I meant conversion between parameters of ab and a+b, for instance, if we had ab and a(b+1) we could.
_________________

Follow your heart Re: a < 0 < b so compare ab and a+b   [#permalink] 03 Dec 2018, 14:31
Display posts from previous: Sort by

# a < 0 < b so compare ab and a+b  Question banks Downloads My Bookmarks Reviews Important topics Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.