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n is an integer.gmattesttaker2 wrote:Hello,
Can you please help with this:
If n is an integer, is n positive?
1) (2n+1)/(n+1) is an integer
2) n = -n
OA: D
Thanks,
Sri
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Statement 1: (2n+1)/(n+1) is an integergmattesttaker2 wrote:Hello,
Can you please help with this:
If n is an integer, is n positive?
1) (2n+1)/(n+1) is an integer
2) n = -n
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C
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But, my calculation says Statement 2 is not sufficient.[email protected] wrote:
Fact 2: N = -N
In the realm of math, there's only one solution to this equal. N must = 0 and the answer to the question is NO.
Fact 2 is SUFFICIENT
Final Answer: B
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Statement 1:GMATGuruNY wrote:Statement 1: (2n+1)/(n+1) is an integergmattesttaker2 wrote:Hello,
Can you please help with this:
If n is an integer, is n positive?
1) (2n+1)/(n+1) is an integer
2) n = -n
In other words, 2n+1 is a multiple of n+1.
If n>0, then the smallest possible multiple of n+1 -- after n+1 itself -- is as follows:
2(n+1) = 2n+2.
Thus, if n>0, it is not possible that 2n+1 -- a value LESS than 2n+2 -- is a multiple of n+1.
Implication:
n cannot be positive.
SUFFICIENT.
Statement 2: n=-n
Adding n to both sides, we get:
2n = 0
n = 0.
Thus, n is not positive.
SUFFICIENT.
The correct answer is D.
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'n is an integer' mean that n is one among {..., -3, -2, -1, 0, 1, 2, 3, ...}gmattesttaker2 wrote:Hello,
Can you please help with this:
If n is an integer, is n positive?
1) (2n+1)/(n+1) is an integer
2) n = -n
OA: D
Thanks,
Sri
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B
C
D
E
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There is a mistake: you're letting n assume two different values in the same equation. (You can't have n be 6 and -6 simultaneously.) I like the idea though!n=-n
n+n=0
integer+integer=0
6+(-6)=0, (the summation of 2 integer will be zero if the integers are same value and carries opposite sign.
So, n=6,-6
---> not sufficient
adding the 2 statements:
The summation of 2 integer must be zero.
So, we can take these values as integer=6 and -6.
So, not sufficient.
Is there any mistake in my calculation?
thanks...
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[email protected] wrote:Hi Sri,
This DS question is perfect for TESTing Values; it also has some Number Properties built into it.
We're told that N is an integer. We're asked if N is positive. This is a YES/NO question.
Fact 1: (2N+1)/(N+1) = an integer.
Let's TEST VALUES:
If N = 0, we have 1/1 = an integer and the answer to the question is NO (because 0 is a "null" value; it is NOT positive).
If N = -2, we have -3/-1 = 3 = an integer and the answer to the question is NO.
When attempting to test a positive integer, we run into a problem....there are NO positive integers that satisfy Fact 1. N cannot be 1,2,3,4,5,etc., so we have no valid test cases that are positive. Based on the information that we DO have, the answer is ALWAYS NO.
Fact 1 is SUFFICIENT
Fact 2: N = -N
In the realm of math, there's only one solution to this equal. N must = 0 and the answer to the question is NO.
Fact 2 is SUFFICIENT
Final Answer: B
GMAT assassins aren't born, they're made,
Rich
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Target question: Is n positive?gmattesttaker2 wrote: ↑Sun Jun 15, 2014 5:47 pmHello,
Can you please help with this:
If n is an integer, is n positive?
1) (2n+1)/(n+1) is an integer
2) n = -n
OA: D
Thanks,
Sri
