Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 26 May 2017, 19:16

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If a^2=b, is the value of a between 0 and 1?

Author Message
TAGS:

### Hide Tags

Intern
Joined: 22 Oct 2012
Posts: 7
Followers: 0

Kudos [?]: 22 [1] , given: 1

If a^2=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

01 Dec 2012, 00:37
1
KUDOS
4
This post was
BOOKMARKED
00:00

Difficulty:

85% (hard)

Question Stats:

41% (02:14) correct 59% (01:15) wrong based on 137 sessions

### HideShow timer Statistics

If a^2=b, is the value of a between 0 and 1?

(1) b is between 0 and 1
(2) a>b
[Reveal] Spoiler: OA

Last edited by Bunuel on 01 Dec 2012, 05:59, edited 1 time in total.
Edited the question.
Senior Manager
Joined: 22 Dec 2011
Posts: 294
Followers: 3

Kudos [?]: 266 [0], given: 32

Re: If a*a=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

01 Dec 2012, 04:15
cv3t3l1na wrote:
If a*a=b, is the value of a between 0 and 1?
1. b is between 0 and 1
2. a>b

Why 2. is not sufficient?

Huh? Inside the spoiler you have given OA as B?

I guess both a sufficient by itself to answer to question "is the value of a between 0 and 1?"

Question rephrase ->$$a*a = b ; a^2 = b ; a = +/- \sqrt{b}$$
Is $$0 < a < 1$$

Stat1/Given B is between 0 and 1.
a= 0.5 then b = 0.25 ; a is in between 0 and 1
a = -0.5 then b = 0.25 ; a is NOT between 0 and 1.
InSufficient

Stat2/ If $$a > b & a =\sqrt{b}$$only values that would satisfy these equations would be value from 0 to 1. Sufficient.

So D it is....

Cheers

Last edited by Jp27 on 01 Dec 2012, 07:23, edited 2 times in total.
Moderator
Joined: 02 Jul 2012
Posts: 1223
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 124

Kudos [?]: 1487 [0], given: 116

Re: If a*a=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

01 Dec 2012, 06:18
Jp27 wrote:
cv3t3l1na wrote:
If a*a=b, is the value of a between 0 and 1?
1. b is between 0 and 1
2. a>b

Why 2. is not sufficient?

Huh? Inside the spoiler you have given OA as B?

I guess both a sufficient by itself to answer to question "is the value of a between 0 and 1?"

Question rephrase ->$$a*a = b ; a^2 = b ; a = \sqrt{b}$$
Is $$0 < a < 1$$

Stat1/ If B is between 0 and 1. Root of any value between 0 and 1 will result in a value larger than B but will still be fraction between 0 and 1. Sufficient

Stat2/ If $$a > b & a =\sqrt{b}$$only values that would satisfy these equations would be value from 0 to 1. Sufficient.

So D it is....

Cheers

If a = -0.5, b =0.25
a = 0.5 , b = 0.25 ...
_________________

Did you find this post helpful?... Please let me know through the Kudos button.

Thanks To The Almighty - My GMAT Debrief

GMAT Reading Comprehension: 7 Most Common Passage Types

Senior Manager
Joined: 22 Dec 2011
Posts: 294
Followers: 3

Kudos [?]: 266 [0], given: 32

Re: If a*a=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

01 Dec 2012, 06:45
MacFauz wrote:
Jp27 wrote:
cv3t3l1na wrote:
If a*a=b, is the value of a between 0 and 1?
1. b is between 0 and 1
2. a>b

Why 2. is not sufficient?

Huh? Inside the spoiler you have given OA as B?

I guess both a sufficient by itself to answer to question "is the value of a between 0 and 1?"

Question rephrase ->$$a*a = b ; a^2 = b ; a = \sqrt{b}$$
Is $$0 < a < 1$$

Stat1/ If B is between 0 and 1. Root of any value between 0 and 1 will result in a value larger than B but will still be fraction between 0 and 1. Sufficient

Stat2/ If $$a > b & a =\sqrt{b}$$only values that would satisfy these equations would be value from 0 to 1. Sufficient.

So D it is....

Cheers

If a = -0.5, b =0.25
a = 0.5 , b = 0.25 ...

I will edit my response...!
Math Expert
Joined: 02 Sep 2009
Posts: 38908
Followers: 7739

Kudos [?]: 106252 [1] , given: 11618

Re: If a^2=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

01 Dec 2012, 06:54
1
KUDOS
Expert's post
If a^2=b, is the value of a between 0 and 1?

$$a^2=b$$ --> $$a=-\sqrt{b}$$ or $$a=\sqrt{b}$$.

(1) b is between 0 and 1. If $$b=\frac{1}{4}$$, then $$a$$ could be $$-\frac{1}{2}$$ (answer NO) or $$\frac{1}{2}$$ (answer YES). Not sufficient.

(2) a>b --> $$a=\sqrt{b}$$ --> $$0<b<1$$. Sufficient.

_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15470
Followers: 649

Kudos [?]: 209 [0], given: 0

Re: If a^2=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

05 Feb 2015, 01:05
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Intern
Joined: 10 Apr 2013
Posts: 14
Location: United States (TX)
Concentration: Finance, Entrepreneurship
GMAT 1: 740 Q50 V41
GPA: 3.3
WE: Analyst (Investment Banking)
Followers: 1

Kudos [?]: 9 [0], given: 14

Re: If a^2=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

02 Sep 2015, 10:02
cv3t3l1na wrote:
If a^2=b, is the value of a between 0 and 1?

(1) b is between 0 and 1
(2) a>b

This graph helped me understand this question:

You can clearly see b as the red diagonal and a^{2} as the blue curve

(1) b is between 0 and 1
You can see that where the red line is between 0 and 1, the blue curve is between -1 and 1

(2) a > b
You can see the only portion of the graph where the red line is above the blue curve is between 0 and 1
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 3299
GPA: 3.82
Followers: 239

Kudos [?]: 2030 [1] , given: 0

If a^2=b, is the value of a between 0 and 1? [#permalink]

### Show Tags

03 Sep 2015, 04:49
1
KUDOS
Expert's post
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and equations ensures a solution.

If a^2=b, is the value of a between 0 and 1?

(1) b is between 0 and 1
(2) a>b

There is nothing to transform in the original condition and the question. WE have 2 variable (a,b) and 1 equation (a^2=b), thus we need 1 more to match the number of variables and equations. Since there is 1 each in 1) and 2), D is likely the answer.

In case of 1), if b=0.04 then the answer is no if a=-0.2 and yes if a=0.2 Thus it is not sufficient.
In case of 2), a>b=a^2, a>a^2, 0>a^2-a, 0>a(a-1), 0<a<1, therefore the answer is yes.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself

If a^2=b, is the value of a between 0 and 1?   [#permalink] 03 Sep 2015, 04:49
Similar topics Replies Last post
Similar
Topics:
2 If b<0, is 5b(a+b)>-a^2-b^2? 1) a+2b>0 2) a+3b>0 3 04 Apr 2017, 01:51
4 If a^2 = b, is 1 > a > 0? 3 17 Aug 2015, 09:31
7 If bc ≠ 0, what is the value of (a^2 - b^2 - c^2)/bc? 6 08 Jun 2015, 03:57
If b is positive, is ab positive? 1. a^2b>0 2. a^2+b=13 7 19 Jul 2010, 06:22
13 Is a^2*b > 0? 22 11 Apr 2017, 10:43
Display posts from previous: Sort by