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

It is currently 20 Sep 2018, 03:50

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

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

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

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

Show Tags

New post 18 Jul 2018, 02:58
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

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

HideShow timer Statistics

Director
Director
User avatar
G
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

New post 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.


The best answer is A.
DS Forum Moderator
avatar
P
Joined: 22 Aug 2013
Posts: 1343
Location: India
Premium Member
Re: Is x^2 – 10x > – 20? (1) 3 < x < 7 (2) 2 < x < 9  [#permalink]

Show Tags

New post 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.

Hence A answer
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

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

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

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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®.