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

Redeem

If is an integer, is mod(x) > 1 ?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |
User avatar
Master | Next Rank: 500 Posts
Posts: 392
Joined: Sun May 16, 2010 2:42 am
Location: Bangalore, India
Thanked: 116 times
Followed by:10 members
GMAT Score:770

by albatross86 » Wed Jul 07, 2010 11:56 am
|x| > 1?

Since we have a case of absolute values of integer values, the best way is to quickly test cases that will prove insufficiency.

1. (1 - 2x)*(1 + x) < 0

x = 0 => Inequality not satisfied
x = 1 => -2 < 0... satisfied
x= -1 => Inequality not satisfied
x = 2 => -9 < 0 ... satisfied.

Thus, |x| could be equal to 1 or greater than 1.
INSUFFICIENT

2. (1 - x)*(1 + 2x) < 0

x = 0 => Inequality not satisfied
x = 1 => Inequality not satisfied
x = -1 => -2 < 0 ... satisfied ...Don't forget negative values when testing cases!
x = 2 => -5 < 0 ... satisfied

Thus, |x| could be equal to 1 or greater than 1.
INSUFFICIENT


Both 1 and 2:

-1, 0 and 1 do not satisfy either one or both of our inequalities and are thus out of the domain. x = 2 satisfies both, as would any higher value.

Thus |x| > 1

SUFFICIENT

Pick C.
~Abhay

Believe those who are seeking the truth. Doubt those who find it. -- Andre Gide
Top
Post new topic Post Reply
• Page 1 of 1