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

 It is currently 23 Oct 2019, 11:20

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 a + b^4 positive?

Author Message
TAGS:

Hide Tags

Manager
Joined: 28 Jun 2018
Posts: 153
Location: India
Concentration: Finance, Marketing
Schools: CUHK '21 (II)
GMAT 1: 650 Q49 V30
GPA: 4
is a + b^4 positive?  [#permalink]

Show Tags

17 Aug 2018, 22:15
3
3
00:00

Difficulty:

75% (hard)

Question Stats:

46% (01:39) correct 54% (01:34) wrong based on 58 sessions

HideShow timer Statistics

is $$a + b^{4}$$ positive?
a) b > a
b) $$b^{2} > a^{2}$$

_________________
Director
Joined: 31 Jul 2017
Posts: 512
Location: Malaysia
GMAT 1: 700 Q50 V33
GPA: 3.95
WE: Consulting (Energy and Utilities)
Re: is a + b^4 positive?  [#permalink]

Show Tags

17 Aug 2018, 22:39
2
GMATbuster92 wrote:
is $$a + b^{4}$$ positive?
a) b > a
b) $$b^{2} > a^{2}$$

I) $$b = 3, a =2$$.. $$a + b^{4}$$ is positive.
$$b = 2, a= -20$$... $$a+b^{4}$$ is negative.

II) $$b = 3, a = 2$$... $$a + b^{4}$$ is positive.
b = $$1/\sqrt{2}$$, a = $$-1/\sqrt{3}$$.... $$a + b^{4}$$ is negative.

Hence, $$E$$.
_________________
If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !!
Intern
Joined: 18 Sep 2017
Posts: 13
Location: India
WE: Consulting (Computer Software)
is a + b^4 positive?  [#permalink]

Show Tags

17 Aug 2018, 23:00
GMATbuster92 wrote:
is $$a + b^{4}$$ positive?
a) b > a
b) $$b^{2} > a^{2}$$

First don't try to pick the numbers for this, Just see if you can find 2 things with the given statements

1. Is a -ve or +ve
2. Is a>b

if you cannot answer any one of the above, the answer comes - it's E
Math Expert
Joined: 02 Aug 2009
Posts: 8023
Re: is a + b^4 positive?  [#permalink]

Show Tags

17 Aug 2018, 23:09
is $$a + b^{4}$$ positive?
a) b > a
a=1 and b=2.....yes
a=-1/3 and b = 0.....no
insuff

b) $$b^{2} > a^{2}$$
a=2, b=4.....yes
a=-1/3 and b = 1/2 ....No
insuff

combined
a=2, b=4.....yes
a=-1/3 and b = 1/2 ....No
insuff

E
_________________
Senior Manager
Joined: 10 Jan 2013
Posts: 302
Location: India
Concentration: General Management, Strategy
GPA: 3.95
Re: is a + b^4 positive?  [#permalink]

Show Tags

18 Aug 2018, 00:00
Hi everyone..

Can we not solve without using numbers?

I took square root b =|b|

But wasn't able to figure out what to do nect

Posted from my mobile device
Manager
Joined: 23 Nov 2017
Posts: 113
Location: Singapore
Concentration: Strategy, Other
Re: is a + b^4 positive?  [#permalink]

Show Tags

18 Aug 2018, 00:16
chetan2u wrote:
is $$a + b^{4}$$ positive?
a) b > a
a=1 and b=2.....yes
a=-1/3 and b = 0.....no
insuff

b) $$b^{2} > a^{2}$$
a=2, b=4.....yes
a=-1/3 and b = 1/2 ....No
insuff

combined
a=2, b=4.....yes
a=-1/3 and b = 1/2 ....No
insuff

E

chetan2u, can we do this without assuming numbers? like algebraically or the number line please?
Re: is a + b^4 positive?   [#permalink] 18 Aug 2018, 00:16
Display posts from previous: Sort by