Is |x-1|<1 for all integers x ?

This topic has expert replies
Legendary Member
Posts: 2276
Joined: Sat Oct 14, 2017 6:10 am
Followed by:3 members

Is |x-1|<1 for all integers x ?

by VJesus12 » Tue Oct 24, 2017 3:24 pm
Is |x-1|<1 for all integers x ?

(1) (x-1)^2 >1.
(2) x<0.

The OA is D.

I got confused here. I don't know how to prove statement (1) is sufficient.
By the other hand, if x<0 (statement 2), then |x-1|>1. Why is it sufficient?

Experts, if you could give me some help I'd be thankful.
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 am
Location: Grand Central / New York
Thanked: 470 times
Followed by:34 members

by Jay@ManhattanReview » Tue Oct 24, 2017 9:44 pm
VJesus12 wrote:Is |x-1|<1 for all integers x ?

(1) (x-1)^2 >1.
(2) x<0.

The OA is D.

I got confused here. I don't know how to prove statement (1) is sufficient.
By the other hand, if x<0 (statement 2), then |x-1|>1. Why is it sufficient?

Experts, if you could give me some help I'd be thankful.
Let's look at the inequality |x-1|<1 closely.

=> -1 < x - 1 < 1 => 0 < x < 2.

Question rephrased: Is 0 < x < 2?

(1) (x-1)^2 >1

=> |x-1| > 1. The result is opposite of what the question asks. The answer is NO. Sufficient.

(2) x < 0

Since the rephrased question asks whether 0 < x and the statement states that x < 0. The answer is NO. Sufficient.

The correct answer: D

Hope this helps!

-Jay

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide
_________________
Manhattan Review GMAT Prep

Locations: New York | Hyderabad | Mexico City | Toronto | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.