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

Redeem

Confused with the Data Sufficiency Problems !

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 490
Joined: Thu Jul 04, 2013 7:30 am
Location: Chennai, India
Thanked: 83 times
Followed by:5 members

Confused with the Data Sufficiency Problems !

by Uva@90 » Thu Jul 04, 2013 7:23 pm
Hi All,
I have basic problem in understanding the Data Sufficiency problem. I have given example below,

Ist Problem,

If n is a positive integer, is x+5 even?
1) x=n+1
2) n=13

In the above mentioned probelm what should I infer whether x+5 is even from option 1 & 2 or whether option 1& 2 helps to find whether x+5 is even or odd ?


Similarly it goes for below mentioned problem too

2nd Problem

Is x=y?
1) (x-50)^2 = (y-50)^2
2) (x+y)(1/x + 1/y) =4

Please provide me the answer.

Thanks in advance.

Regards,
Uva.
Top
Source: — Data Sufficiency |
User avatar
Master | Next Rank: 500 Posts
Posts: 490
Joined: Thu Jul 04, 2013 7:30 am
Location: Chennai, India
Thanked: 83 times
Followed by:5 members

by Uva@90 » Thu Jul 04, 2013 8:09 pm
If I am not clear in the above examples,
below is one more question
Question
https://postimg.cc/image/m0aac64cp/full/

In the above link should we analyse whether option 1 & 2 hleps to find whether n > 24 or
n >24 or not.
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Fri Jul 05, 2013 7:49 am
Please post only one question per thread. Otherwise things can become pretty complicated when there are discussions on multiple questions.

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 358
Joined: Thu Apr 18, 2013 9:46 am
Location: Jeddah, Saudi Arabia
Thanked: 42 times
Followed by:7 members
GMAT Score:730

by faraz_jeddah » Sat Jul 06, 2013 8:41 am
Uva@90 wrote:Hi All,
I have basic problem in understanding the Data Sufficiency problem. I have given example below,

Ist Problem,

If n is a positive integer, is x+5 even?
1) x=n+1
2) n=13

In the above mentioned probelm what should I infer whether x+5 is even from option 1 & 2 or whether option 1& 2 helps to find whether x+5 is even or odd ?
Your goal is to be able to answer the question with only one answer i.e x+5 is EVEN or x+5 is ODD. If you can reach to one of these conclusions then the statement(s) are sufficient.

Statement 1 tells you
x = n+1
which means either
n is odd and x is even
OR
n is even and x is odd

This results in different answers to the question Is x+5 even? ==> Insufficient

Example
n = 1 ; x = 2 ==> x + 5 = 7 (ODD)
n = 2 ; x = 3 ==> x + 5 = 8 (EVEN)

If you get multiple answers from the same statement it is always INSUFFICIENT.

Statement 2:
n = 13
No infomration about x ==> Insufficient

Statements 1 & 2 Together

you can tell the value of x which is 14 and answer the question is x+5 is even? 14+5 = 19 which is DEFINITELY NOT EVEN.

Hope that helps.
Top
Newbie | Next Rank: 10 Posts
Posts: 2
Joined: Sun Apr 22, 2012 11:59 pm
Followed by:2 members

by karishma.shrivastava » Sat Jul 06, 2013 9:26 pm
Is x=y?
1) (x-50)^2 = (y-50)^2
2) (x+y)(1/x + 1/y) =4


For this question-

1) (x-50)^2 = (y-50)^2

(x-50)^2-(y-50)^2=0
(x-50-y+50)(x+y-100)=0
So either (x-y)=0 or (x+y-100)=0

So (1) is INSUFFICIENT to answer the question

2) (x+y)(1/x + 1/y) =4
(x+y)(x+Y)=4xy
x^2+y^2+2xy-4xy=0
(x-y)^2=0

So (2) is SUFFICIENT to answer the question

Hence the Answer will be B.
Top
Post new topic Post Reply
• Page 1 of 1