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

 It is currently 15 Aug 2018, 09:45

### 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

# DS: Inequality, 700-800 Ranking

Author Message
Manager
Joined: 15 Jul 2008
Posts: 205
Re: DS: Inequality, 700-800 Ranking  [#permalink]

### Show Tags

29 Aug 2008, 08:41
x2suresh wrote:
lexis wrote:

$$Green: x^3>y Blue: sqrt{x}>y Pink: x>y$$

NICE FIGURE.. Good job.

Is this figure saying the answer is E ??!!
SVP
Joined: 07 Nov 2007
Posts: 1728
Location: New York
Re: DS: Inequality, 700-800 Ranking  [#permalink]

### Show Tags

29 Aug 2008, 08:52
bhushangiri wrote:
x2suresh wrote:
lexis wrote:

$$Green: x^3>y Blue: sqrt{x}>y Pink: x>y$$

NICE FIGURE.. Good job.

Is this figure saying the answer is E ??!!

Its saying C... anything below x=y line is x>y..
IN this figure dark dots represent ... combined area.. which is always below x=y line i.e x>y
_________________

Smiling wins more friends than frowning

Manager
Joined: 15 Jul 2008
Posts: 205
Re: DS: Inequality, 700-800 Ranking  [#permalink]

### Show Tags

29 Aug 2008, 08:54
I have a question. When we have the condition sqrt(x) > y... why are we not considering the red shaded region alone? This regions satisfies both +ve and -ve aspects of the sqrt.
Attachments

UpNhAnHdotC0M2008082924135ota4ztqwow152812.jpeg [ 72.13 KiB | Viewed 812 times ]

SVP
Joined: 29 Aug 2007
Posts: 2420
Re: DS: Inequality, 700-800 Ranking  [#permalink]

### Show Tags

29 Aug 2008, 09:24
lexis wrote:

1: sqrt(x) > y.

if x is 0.36 and y = 0.3, sqrtx > y and x > y.
if x is 0.25 and y = 0.3, sqrtx > y but x < y.
so nsf.... but we know here x is +ve

2. x^3 > y

if x is 6 and y = 5 x^3 > y and x > y.
if x is 2 and y = 5, x^3 > y but x < y.

so nsf.... but we do not know whether x and y are +ve ( or -ve).

togather form 1 and 2:
first, it is clear that x is +ve.
second, to hold both statements (sqrt (x) > y and x^3 > y) true, x has to be > y.

So C for me..
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

GMAT Tutor
Joined: 24 Jun 2008
Posts: 1345
Re: DS: Inequality, 700-800 Ranking  [#permalink]

### Show Tags

29 Aug 2008, 11:09
I'm pretty sure on the real GMAT the question would specify that x was positive in the stem. In any case, presenting essentially the same reasoning as Kevin,

$$\text{If } x > 1 \text{, then } \sqrt{x} < x < x^3 \text{ so if } y \text{ is less than both } \sqrt{x} \text{ and } x^3 \text{, } y \text{ must be less than } x \\ \text{If } 0 < x < 1 \text{, then } x^3 < x < \sqrt{x} \text{ so if } y \text{ is less than both } \sqrt{x} \text{ and } x^3 \text{, } y \text{ must be less than } x \\ \text{If } x = 1 \text{ or } 0 \text{, then } x^3 = x = \sqrt{x} \text{ so if } y \text{ is less than both } \sqrt{x} \text{ and } x^3 \text{, } y \text{ must be less than } x \\$$

So C. Note that while every positive number has two square roots, $$\sqrt{x}$$ has only one value: the non-negative square root of x.
_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

Senior Manager
Joined: 07 Jan 2008
Posts: 369
Re: DS: Inequality, 700-800 Ranking  [#permalink]

### Show Tags

29 Aug 2008, 23:10
bhushangiri wrote:
I have a question. When we have the condition sqrt(x) > y... why are we not considering the red shaded region alone? This regions satisfies both +ve and -ve aspects of the sqrt.

$$sqrt{x} >0$$ with all x>=0 So, if y $$sqrt{x} >y$$ with all x>0.

It is different from case $$x >y^2$$
In the case, the shaded zone is "inner" the parabol!

Hope it helps!

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: DS: Inequality, 700-800 Ranking &nbs [#permalink] 29 Aug 2008, 23:10

Go to page   Previous    1   2   [ 26 posts ]

Display posts from previous: Sort by

# Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.