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

Redeem

DS on Absolute value

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 141
Joined: Sat Feb 28, 2009 8:19 am
Thanked: 1 times

DS on Absolute value

by getso » Sat Apr 24, 2010 8:51 am
What is the value of modulus of ( x+7)
(1) modulus of (x+3)= 14
(2) (x + 2)^2 = 169

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.


Ans is D...but I feel it should be C
Last edited by getso on Sat Apr 24, 2010 9:02 am, edited 2 times in total.
Top
Source: — Data Sufficiency |
User avatar
Master | Next Rank: 500 Posts
Posts: 170
Joined: Wed Jun 10, 2009 5:59 am
Thanked: 13 times

by iamseer » Sat Apr 24, 2010 9:00 am
can't see the characters correctly. please do the needful
"Choose to chance the rapids and dance the tides"
Top
User avatar
Legendary Member
Posts: 1560
Joined: Tue Nov 17, 2009 2:38 am
Thanked: 137 times
Followed by:5 members

by thephoenix » Sat Apr 24, 2010 9:14 am
agreed it has to be C
wats the source
Top
Master | Next Rank: 500 Posts
Posts: 141
Joined: Sat Feb 28, 2009 8:19 am
Thanked: 1 times

by getso » Sat Apr 24, 2010 9:31 am
Source I'm not really sure..

I have a doc file which says questions are from previous OG and GMAT.

Thanks,
Shobha
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 170
Joined: Wed Jun 10, 2009 5:59 am
Thanked: 13 times

by iamseer » Sat Apr 24, 2010 10:21 am
from 1:
x= 11 or -17, not sufficient

from 2:
x= 11 or -15, not sufficient

combining 1and 2
x=11

Answer C
"Choose to chance the rapids and dance the tides"
Top
User avatar
Legendary Member
Posts: 526
Joined: Sat Feb 21, 2009 11:47 pm
Location: India
Thanked: 68 times
GMAT Score:680

by harshavardhanc » Sun Apr 25, 2010 1:16 am
getso wrote:What is the value of modulus of ( x+7)
(1) modulus of (x+3)= 14
(2) (x + 2)^2 = 169

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.


Ans is D...but I feel it should be C
It has to be C.

The question asks us to find the distance of x from -7.

St1 says : distance of x from -3 is 14.

so, x can be on the either side of -3 at a distance 14, which will give us different values of distance from -7. Not sufficient.

St2 says : (x+2)^2 = 169 which can be re-written as |x+2|^2 = 169 or |x+2| = 13

or distance of x from -2 is 13 units.

Not sufficient, as the point can be on the either side of -2 at a distance 13, which will give us different values of distance from -7 .

Combining we get, that X is at a distance 14 from -3 and 13 from -2, which indicates that x is on right side of these two points and therefore on the right of -7 as well and at a distance of 18 units from -7.
Last edited by harshavardhanc on Sun Apr 25, 2010 3:45 am, edited 1 time in total.
Regards,
Harsha
Top
GMAT Instructor
Posts: 1302
Joined: Mon Oct 19, 2009 2:13 pm
Location: Toronto
Thanked: 539 times
Followed by:164 members
GMAT Score:800

by Testluv » Sun Apr 25, 2010 1:50 am
The correct answer is definitely choice C, and both harsha and iamseer's approaches are great.

_______
What is the value of modulus of ( x+7) ?
(1) modulus of (x+3)= 14
(2) (x + 2)^2 = 169
In a value DS question, a statement needs to provide one and only one value to be sufficient.

Because (1) gives an absolute value equation, (1) will lead to two possible values. Insufficient. Eliminate A and D.

Because (2) gives a square, (2) will also lead to two possible values. Eliminate B....the answer will be C or E.

(1) + (2):

From (1), x can be either 11 or -17.

In (2) we see that the right hand side is 13^2 or (-13)^2. So, as harsha points out, either x + 2 = 13 or else x + 2 = -13. So, either x = 11 or else x = -15. Because, together, there is only one shared value (11), the statements are sufficient when combined.

Choose C.
Kaplan Teacher in Toronto
Top
Post new topic Post Reply
• Page 1 of 1