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

It is currently 12 Dec 2019, 20:18

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^2 = b, is 1 > a > 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: 59712
If a^2 = b, is 1 > a > 0?  [#permalink]

Show Tags

New post 29 Jul 2015, 03:11
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

40% (01:47) correct 60% (01:52) wrong based on 196 sessions

HideShow timer Statistics

Manager
Manager
User avatar
B
Joined: 14 Mar 2014
Posts: 142
GMAT 1: 710 Q50 V34
Re: If a^2 = b, is 1 > a > 0?  [#permalink]

Show Tags

New post 29 Jul 2015, 03:46
Bunuel wrote:
If a^2 = b, is 1 > a > 0?

(1) 1 > b > 0
(2) a > b

Kudos for a correct solution.



IMO : B

Statement 1: 0< b< 1

if b lies in 0< b< 1 then
a can lie in 0< a< 1 or -1 < a< 0.
For eg: if b = 1/4 then a can be 1/2 or -1/2 .
Not suff

Statement 2: a > b
Given \(a^2 = b\) i.e b >=0. And if a>b then a must also be >=0
If a>b then
for a>1 then \(a^2 > b\). They cannot be equal
so a must be in interval 0<a<1

PS: a cannot be equal to "0" or "1" since it violates the statement 2: a>b
Retired Moderator
avatar
Joined: 29 Apr 2015
Posts: 816
Location: Switzerland
Concentration: Economics, Finance
Schools: LBS MIF '19
WE: Asset Management (Investment Banking)
GMAT ToolKit User
Re: If a^2 = b, is 1 > a > 0?  [#permalink]

Show Tags

New post 29 Jul 2015, 03:50
2
Bunuel wrote:
If a^2 = b, is 1 > a > 0?

(1) 1 > b > 0
(2) a > b

Kudos for a correct solution.


Statement 1:
If 1>b>0 and a^2 = b, >>> A must be a fraction e.g. 1/2^2 = 1/4 or -1/2^2=1/4. Resulting in Yes/No for the question above. IS.

Statement 2:
a > b tells us that, a is positive since a^2 = b (which must be positive). Therefore a must be a positive fraction e.g. 1/2, 3/4 ...

Answer B.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 59712
Re: If a^2 = b, is 1 > a > 0?  [#permalink]

Show Tags

New post 17 Aug 2015, 09:31
Bunuel wrote:
If a^2 = b, is 1 > a > 0?

(1) 1 > b > 0
(2) a > b

Kudos for a correct solution.


800score Official Solution:

Statement (1) tells us that b is between 0 and 1, so we also know that a² is between 0 and 1 since b = a². If a is any number between -1 and 1, then a² will be
between 0 and 1, so Statement (1) is insufficient.

Statement (2) tells us that a > b, and since a² = b, we know that a > a². This is only true for
numbers between 0 and 1. The square of any number that is larger than 1 or negative will be larger than the number itself. So Statement (2) is sufficient.

Since Statement (1) is insufficient and Statement (2) is sufficient, the correct answer is choice (B).
_________________
Intern
Intern
avatar
B
Joined: 15 Feb 2017
Posts: 1
Re: If a^2 = b, is 1 > a > 0?  [#permalink]

Show Tags

New post 12 Feb 2019, 15:07
I did it differently... Don't know if I'm right.

I restated the question first.

a^2=b (1)

1>a>0 It is the same as 0<a<1.

The inequality that can result in a range like that is:

a*(a-1)<0

So now we have:

a^2-a<0 , as we already know from (1), a^2=b so,

b-a<0
b<a

So our question is is a>b?

The only clear statement that gives us information about a & b is statement (2). So B is the answer.
GMAT Club Bot
Re: If a^2 = b, is 1 > a > 0?   [#permalink] 12 Feb 2019, 15:07
Display posts from previous: Sort by

If a^2 = b, is 1 > a > 0?

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





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