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

 It is currently 20 Sep 2018, 03:50

### 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 x^2 – 10x > – 20? (1) 3 < x < 7 (2) 2 < x < 9

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 49272
Is x^2 – 10x > – 20? (1) 3 < x < 7 (2) 2 < x < 9  [#permalink]

### Show Tags

18 Jul 2018, 02:58
00:00

Difficulty:

35% (medium)

Question Stats:

75% (02:09) correct 25% (02:17) wrong based on 24 sessions

### HideShow timer Statistics

Is x^2 – 10x > – 20?

(1) 3 < x < 7

(2) 2 < x < 9

_________________
Director
Joined: 31 Oct 2013
Posts: 573
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
Is x^2 – 10x > – 20? (1) 3 < x < 7 (2) 2 < x < 9  [#permalink]

### Show Tags

18 Jul 2018, 03:24
Bunuel wrote:
Is x^2 – 10x > – 20?

(1) 3 < x < 7

(2) 2 < x < 9

Statement 1 :

x ( minimum)= 4

x ( maximum) = 6

So,

$$(4)^2$$ - 10*4 > -20

16 -40 < -20

- 24 < -20

and

$$6^2$$- 10*6 > -20

- 24 < - 20

Sufficient

Statement 2:

x (minimum) = 3

x (maximum) =8

$$(3)^2$$ -10*3 > -20

-21 < -20

and

$$8^2$$ - 10*8 > -20

- 16 > -20

Not Sufficient.

DS Forum Moderator
Joined: 22 Aug 2013
Posts: 1343
Location: India
Re: Is x^2 – 10x > – 20? (1) 3 < x < 7 (2) 2 < x < 9  [#permalink]

### Show Tags

18 Jul 2018, 21:23
Bunuel wrote:
Is x^2 – 10x > – 20?

(1) 3 < x < 7

(2) 2 < x < 9

We can rewrite the question stem as x^2 - 10x + 20 > 0
Or (x-5)^2 - 5 > 0. Or Is (x-5)^2 > 5.

Square root of 5 is approximately 2.24. So the thing given in question stem will be true if x-5 > 2.24 or if x-5 < -2.24
OR it will be true if x > 7.24 or if x < 2.76.

(1) x lies between 3 and 7. So x can be neither greater than 7.24 nor less than 2.76. So the question stem can never be true. Sufficient to answer with a NO.

(2) x lies between 2 and 9. But it can still be greater than 7.24 or it might not. Not sufficient.

Re: Is x^2 – 10x > – 20? (1) 3 < x < 7 (2) 2 < x < 9 &nbs [#permalink] 18 Jul 2018, 21:23
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®.