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[DS][square] HSPA posts

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[DS][square] HSPA posts

by HSPA » Sun Apr 10, 2011 3:39 am
Is the positive integer n equal to the square of an integer?
(1) For every prime number p, if p is a divisor of n, then so is p^2.
(2) root n is an integer
First take: 640 (50M, 27V) - RC needs 300% improvement
Second take: coming soon..
Regards,
HSPA.
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Source: — Data Sufficiency |
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by vineeshp » Sun Apr 10, 2011 5:15 am
(1) For every prime number p, if p is a divisor of n, then so is p^2.
NS.
if n =18, above stmt hold but n is not square of an integer.

(2) root n is an integer
if root n is an integer i, then n = i ^2.
SO Sufficient.

B
Vineesh,
Just telling you what I know and think. I am not the expert. :)
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by force5 » Sun Apr 10, 2011 5:16 am
IMO - B

(1) n has factors of p^2 - not true for all cases n=9 ( true) n=18 not true.
(2) root n is an integer
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by tpr-becky » Tue Apr 12, 2011 7:08 am
I agree with the above:

Statment 1 tells you that n has both a prime number and it's square as factors but this does not tell you the value of n or whether n is a square of an integer. if p =2 then n could be 4 (has 2 and 4 as divisors) or it could be 18 (has 3 and 9 as divisors). Insufficient - BCE is left.

2) tells you that the square root of n is an integer - the only way for the square root to be an integer is if the number is an integer squared. Therefore it is sufficient and B is your answer.

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by HSPA » Tue Apr 12, 2011 5:01 pm
thank you all for helping me on this thread... OA is... as you said...
First take: 640 (50M, 27V) - RC needs 300% improvement
Second take: coming soon..
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HSPA.
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by [email protected] » Fri Jul 29, 2011 1:53 pm
THE ANSWER SHOULD BE D.
FROM 1: IF P IS A DIVISIOR OF N THAN P SQUARE IS ALSO A DIVISOR OF N. IT MEANS IF 2 IS A DIVISOR OF N THAN 4 IS ALSO A DIVISOR OF N :::::::::::::: OTHER EG. IF 2 AND 3 ARE THE DIVISOR OF N THAN BOTH 2 SQUARE AND 3 SQUARE ARE DIVISOR OF N. THUS SUFFICIENT.

WELL I CAN'T EXPLAIN MY THOUGHT IN MY WORDS. BUT A IS SUFFICIENT. I AM 100 % SURE.
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