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

Redeem

Is x odd

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
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 » Fri Jan 26, 2018 3:53 am
lheiannie07 wrote:Is x odd?

(1) x/2 is not an integer

(2) 2x + 3 is odd
Statement 1:
Since x/2 is not an integer, x cannot be EVEN.
Be sure to test NON-INTEGER values.

Case 1: x=1, with the result that x/2 = 1/2
In this case, the answer to the question stem is YES.
Case 2: x=1/2, with the result that x/2 = 1/4
In this case, the answer to the question stem is NO.

Since the answer is YES in Case 1 but NO in Case 2, INSUFFICIENT.

Statement 2:
2x + 3 = 1, 3, 5, 7, 9, 11...
Subtracting 3 from every value, we get:
2x = -2, 0, 2, 4, 6, 8...
Dividing every value by 2, we get:
x = -1, 0, 1, 2, 3, 4...
The resulting blue list indicates that x can be ANY INTEGER VALUE.
Since x can be odd or even, INSUFFICIENT.

Statements combined:
Statement 2 --> x must be an integer.
Statement 1 --> x cannot be even.
Since x must be an integer that is not even, x is ODD.
SUFFICIENT.

The correct answer is C.
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
Legendary Member
Posts: 712
Joined: Fri Sep 25, 2015 4:39 am
Thanked: 14 times
Followed by:5 members

by Mo2men » Fri Jan 26, 2018 6:20 am
GMATGuruNY wrote:
lheiannie07 wrote:Is x odd?

(1) x/2 is not an integer

(2) 2x + 3 is odd
Statement 1:
Since x/2 is not an integer, x cannot be EVEN.
Be sure to test NON-INTEGER values.

Case 1: x=1, with the result that x/2 = 1/2
In this case, the answer to the question stem is YES.
Case 2: x=1/2, with the result that x/2 = 1/4
In this case, the answer to the question stem is NO.

Since the answer is YES in Case 1 but NO in Case 2, INSUFFICIENT.

Statement 2:
2x + 3 = 1, 3, 5, 7, 9, 11...
Subtracting 3 from every value, we get:
2x = -2, 0, 2, 4, 6, 8...
Dividing every value by 2, we get:
x = -1, 0, 1, 2, 3, 4...
The resulting blue list indicates that x can be ANY INTEGER VALUE.
Since x can be odd or even, INSUFFICIENT.

Statements combined:
Statement 2 --> x must be an integer.
Statement 1 --> x cannot be even.
Since x must be an integer that is not even, x is ODD.
SUFFICIENT.

The correct answer is C.
Dear Mitch,
If the question stem says: is the integer x odd?, then is statement 1 sufficient on its own?

Thanks
Top
Post new topic Post Reply
• Page 1 of 1