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

Redeem

Struggle with Modulus questions

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 1077
Joined: Mon Dec 13, 2010 1:44 am
Thanked: 118 times
Followed by:33 members
GMAT Score:710

by bblast » Sun Jul 10, 2011 6:40 am
hi,
decode statement 1 by taking two possible values of LHS of the eq's.

first take -x-1 = 2x-2.
which gives x = 1/3

then take x+1 = 2x-2
whih gives x = 3

now check if both these satisfy statement 1.

they do, hence statement 1 is not sufficient,

2 negates one of the values obtained above.

hence answer is c

x =1/3
Cheers !!

Quant 47-Striving for 50
Verbal 34-Striving for 40

My gmat journey :
https://www.beatthegmat.com/710-bblast-s ... 90735.html
My take on the GMAT RC :
https://www.beatthegmat.com/ways-to-bbla ... 90808.html
How to prepare before your MBA:
https://www.youtube.com/watch?v=upz46D7 ... TWBZF14TKW_
Top
Junior | Next Rank: 30 Posts
Posts: 16
Joined: Mon May 23, 2011 3:30 am

by abhishekswamy » Sun Jul 10, 2011 6:47 am
bblast wrote:hi,
decode statement 1 by taking two possible values of LHS of the eq's.

first take -x-1 = 2x-2.
which gives x = 1/3

then take x+1 = 2x-2
whih gives x = 3

now check if both these satisfy statement 1.

they do, hence statement 1 is not sufficient,

2 negates one of the values obtained above.

hence answer is c

x =1/3
Bblast: can you please explain...you have taken two case for LHS i.e when |x-1| is positive and negative,y not 2 cases for RHS also??
Top
User avatar
Legendary Member
Posts: 1077
Joined: Mon Dec 13, 2010 1:44 am
Thanked: 118 times
Followed by:33 members
GMAT Score:710

by bblast » Sun Jul 10, 2011 7:07 am
Hi abhishek,

actually there are 4 cases :

lhs -ve rhs +ve case1
lhs -ve rhs -ve case2

lhs +ve rhs +ve case3
lhs +ve rhs -ve case4


As u can see case 2 and case 3 above are the same. similarly case 1 and case 4 are the same.
which are the actual 2 cases u need to consider.
Cheers !!

Quant 47-Striving for 50
Verbal 34-Striving for 40

My gmat journey :
https://www.beatthegmat.com/710-bblast-s ... 90735.html
My take on the GMAT RC :
https://www.beatthegmat.com/ways-to-bbla ... 90808.html
How to prepare before your MBA:
https://www.youtube.com/watch?v=upz46D7 ... TWBZF14TKW_
Top
Master | Next Rank: 500 Posts
Posts: 111
Joined: Tue Dec 30, 2008 1:25 pm
Location: USA
Thanked: 28 times
GMAT Score:770

by goalevan » Mon Jul 11, 2011 3:49 pm
-1 < x < 1?

Statement 1) |x + 1| = 2|x - 1| has two cases:

x + 1 = 2x - 2
x = 3

x + 1 = -(2x - 2)
3x = 1
x = 1/3

We always verify that both solutions satisfy the original equation:

|3 + 1| = 2|3 - 1|
|4| = 2|2|

|1/3 + 1| = 2|1/3 - 1|
|4/3| = 2|-2/3|

With these two possible values of x, statement 1 is not sufficient:

-1 < 1/3 < 1? yes
-1 < 3 < 1? no

Statement 2) |x - 3| ≠ 0

x - 3 ≠ 0
x ≠ 3

Note that no second case exists in this equation since -0 = 0.

With different possible values of x, statement 2 is not sufficient:

-1 < 0 < 1? yes
-1 < -500,000,000 < 1? no

Combined)
x = 3 OR x = 1/3
AND x ≠ 3
x = 1/3

-1 < 1/3 < 1

Sufficient.

C
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 461
Joined: Tue May 10, 2011 9:09 am
Location: pune
Thanked: 36 times
Followed by:3 members

by amit2k9 » Mon Jul 11, 2011 9:10 pm
we need to check if -1<x<1

a for 0.3<x<0.4 the LHS approx = RHS.
for x=3 LHS= RHS. not sufficient.

b x # 3 not sufficient.

a+b

x=0.33. sufficient.
C it is.
For Understanding Sustainability,Green Businesses and Social Entrepreneurship visit -https://aamthoughts.blocked/
(Featured Best Green Site Worldwide-https://bloggers.com/green/popular/page2)
Top
Post new topic Post Reply
• Page 1 of 1