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 Post subject: What is the Value of √x ---Experts Please Help!!!
 Post Posted: Tue Jun 23, 2009 3:01 am 
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Students


Posts: 27
If √x is an integer, what is the value of √x?

1.) 11<x<17
2.) 2<√x<5

Kindly tell me when do we consider only the positive square root of a variable.....

According to me if x>0 and x=16 then √x will be only 4 and not 4 and (-4 ) both....

And if X<0 then we consider both the positive and negative roots...Please correct me if i am wrong!!

please clear this confusion of mine!!!!

IN GMAT land square root of a number is positive.

Please Explain this rule to me!!!I dont know what am i missing!!

PLEASE HELP!!!!

Regards,
Apoorva


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 Post subject: Re: What is the Value of √x ---Experts Please Help!!!
 Post Posted: Wed Jun 24, 2009 6:52 am 
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ManhattanGMAT Staff


Posts: 4420
hi.

the symbol "√" refers ONLY to the POSITIVE square root of the number.

this is a convention.
there has to be SOME convention; you certainly can't walk around with symbols that mean two things at once.

if you want the positive square root of 9 (which equals 3), you write √9.
if you want the negative square root of 9 (which equals -3), you write -√9.

Quote:
Kindly tell me when do we consider only the positive square root of a variable.....


whenever you see "√", it refers only to the positive square root.

Quote:
According to me if x>0 and x=16 then √x will be only 4 and not 4 and (-4 ) both....


correct.

i'm not sure of your point in writing "x > 0" here. if x = 16, then that is clearly positive.

but, yes.

Quote:
And if X<0 then we consider both the positive and negative roots...


no.

if x < 0, then √x doesn't exist at all, so you don't have to worry about this in the first place.
(negative numbers don't have square roots.)


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 Post subject: Re: What is the Value of √x ---Experts Please Help!!!
 Post Posted: Sat Jul 18, 2009 2:20 pm 
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Students


Posts: 1
what is the correct answer here?


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 Post subject: Re: What is the Value of √x ---Experts Please Help!!!
 Post Posted: Sat Jul 18, 2009 11:21 pm 
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Students


Posts: 60
Quote:
If √x is an integer, what is the value of √x?

1.) 11<x<17
2.) 2<√x<5


Given Data,
√x is an integer

Stmt 1:
11<x<17

so If √x is an integer, then fron (1) x = 16, so √x = 4 - SUFFICIENT

Stmt 2:
2<√x<5 here √x could be either 3 or 4. So INSUFFICIENT


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 Post subject: Re: What is the Value of √x ---Experts Please Help!!!
 Post Posted: Tue Jul 21, 2009 6:13 pm 
Offline
ManhattanGMAT Staff


Posts: 4420
yeah, poster above me is correct. the answer should be (a).

by the way, this doesn't seem like an OFFICIAL GMATPREP QUESTION (the only type of question that's supposed to be in this particular folder).
it certainly could be one, but it doesn't seem like one.


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