BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

(sqrt)n

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 13
Joined: Fri Sep 27, 2013 4:44 am

(sqrt)n

by Malolo355 » Tue Apr 22, 2014 7:28 am
"If n is a positive integer, is n equal to 100?
(1) (sqrt)n > 9
(2) (sqrt)n < 11 "
According to the first statement n could be 100 or 121 or 144 or 169 and so on. So it's insufficient.
Statement 2 is also insufficient since n could 100 or 81 or 64 or 49 etc...
But if we combine them the result is n=100. So it should be C.
What is the O.A?
Top
Source: — Data Sufficiency |
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Tue Apr 22, 2014 7:36 am
Malolo355 wrote:"If n is a positive integer, is n equal to 100?
(1) (sqrt)n > 9
(2) (sqrt)n < 11 "
According to the first statement n could be 100 or 121 or 144 or 169 and so on. So it's insufficient.
Statement 2 is also insufficient since n could 100 or 81 or 64 or 49 etc...
But if we combine them the result is n=100. So it should be C.
What is the O.A?
Statement 1: √n > 9
Squaring both sides, we get:
n > 81.
Since n can be ANY INTEGER greater than 81, INSUFFICIENT.

Statement 2: √n < 11
Squaring both sides, we get:
n < 121.
Since n can be ANY POSITIVE INTEGER less than 121, INSUFFICIENT.

Statements combined:
Since n can be ANY INTEGER between 81 and 121, INSUFFICIENT.

The correct answer is E.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Junior | Next Rank: 30 Posts
Posts: 13
Joined: Fri Sep 27, 2013 4:44 am

by Malolo355 » Tue Apr 22, 2014 7:40 am
So in other words you claim that (sqrt)n could be a non-integer ?
Top
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Tue Apr 22, 2014 7:44 am
Malolo355 wrote:So in other words you claim that (sqrt)n could be a non-integer ?
While the value of n itself must be an integer, nothing in the problem requires that √n be an integer.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Tue Apr 22, 2014 1:29 pm
Hi Malolo355,

DS Questions are built to test a number of traits: organization, thoroughness, accuracy, attention-to-detail, etc.

Occasionally, you'll have to consider non-integers (fractions, decimals, etc.) when dealing with a DS question (and even some PS questions require a focus on non-integers). It doesn't happen very often, but if your goal is to score at a high level in the Quant, you have to be prepared to do a bit more work and think about more possibilities than just integers.

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Post new topic Post Reply
• Page 1 of 1