It is currently 18 Dec 2018, 15:16

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

a < 0 < b so compare ab and a+b

Author Message
TAGS:
GMAT Club Legend
Joined: 07 Jun 2014
Posts: 4756
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 93

Kudos [?]: 1667 [1] , given: 396

a < 0 < b so compare ab and a+b [#permalink]  27 Oct 2016, 12:44
1
KUDOS
Expert's post
00:00

Question Stats:

56% (00:42) correct 43% (00:38) wrong based on 48 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

GMAT Club Legend
Joined: 07 Jun 2014
Posts: 4756
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 93

Kudos [?]: 1667 [1] , given: 396

Re: a < 0 < b so compare ab and a+b [#permalink]  27 Oct 2016, 12:47
1
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 [1] , given: 18

Re: a < 0 < b so compare ab and a+b [#permalink]  21 Jul 2017, 02:47
1
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: 1253
Followers: 47

Kudos [?]: 1159 [1] , given: 7

Re: a < 0 < b so compare ab and a+b [#permalink]  24 Jul 2017, 14:37
1
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

RELATED VIDEO

_________________

Brent Hanneson – Creator of greenlighttestprep.com

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

Kudos [?]: 38 [0], given: 38

Re: a < 0 < b so compare ab and a+b [#permalink]  07 Mar 2018, 04:36
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.

GMAT Club Legend
Joined: 07 Jun 2014
Posts: 4756
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 93

Kudos [?]: 1667 [0], given: 396

Re: a < 0 < b so compare ab and a+b [#permalink]  07 Mar 2018, 15:56
Expert's post
boxing506 wrote:
please add the minus before 1/2 or revise it not to create confusion

_________________

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: 126
Followers: 2

Kudos [?]: 77 [1] , given: 15

Re: a < 0 < b so compare ab and a+b [#permalink]  07 Mar 2018, 20:10
1
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.

_________________

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

Kudos [?]: 2 [0], given: 0

Re: a < 0 < b so compare ab and a+b [#permalink]  12 Mar 2018, 01:26
D is correct
Intern
Joined: 13 Nov 2018
Posts: 7
Followers: 0

Kudos [?]: 1 [0], given: 6

Re: a < 0 < b so compare ab and a+b [#permalink]  03 Dec 2018, 04:44
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.

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: 7
Followers: 0

Kudos [?]: 1 [0], given: 6

Re: a < 0 < b so compare ab and a+b [#permalink]  03 Dec 2018, 04:44
Manager
Joined: 22 Feb 2018
Posts: 126
Followers: 2

Kudos [?]: 77 [0], given: 15

Re: a < 0 < b so compare ab and a+b [#permalink]  03 Dec 2018, 14:31
asfandiar 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.

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.
_________________

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