Is x positive? (1) 1/(x+1)

Question

Is x positive?

(1) 1/(x+1) < 1/(x-1) where x ≠ 1; x ≠ -1
(2) x is even

chetan2u · Answer

(1) \frac{1}{(x+1)} < \frac{1}{(x-1)} where x ≠ 1; x ≠ -1 \frac{1}{(x-1)} - \frac{1}{(x+1)}>0 \frac{x+1-(x-1)}{(x-1)(x+1)}>0 \frac{2}{x^2-1}>0...........x^2-1>0.......x^2>1 So x<-1 or x>1..... Insuff (2) x is even Insuff Combined x can be -2 or 2... Insuff E

Harsh9676 · Answer

IMO E

Plugging in Nos (keep in mind ZONEF)

1. Plugging in Zero in S1, we get 1<-1, which doesn't satisfy the condition
2. We cannot take 1, since X is not equal to 1
3. Negative no>> Plugging in -2, we get -1<-1/3, which is true and X is negative here
4. Trying X =2, we get 1/3 < 1 which is true again, and X is Positive here.
5. No need to try Exponents and fractions .

St2: Insufficient,

Combined: Again 2 and -2 would give diff solutions.

Ans E

Pankaj0901 · Answer

Sorry, I have a silly question: Are -2, -4, -6 etc even numbers? Negative numbers can be even or odd as well? 
What about 0: Is 0 considered even or odd?

Bunuel · Answer

An even number is an   integer   that is "evenly divisible" by 2, i.e., divisible by 2 without a remainder. So, ..., -4, -2,  0 , 2, 4, ... are all even integers.

An odd number is an   integer   that is not evenly divisible by 2. So, ..., -3, -1, 1, 3, 5, ... are all odd integers.

Harsh9676 · Answer

Yes negative numbers can be even or odd.

And 0 is even

Posted from my mobile device

Pankaj0901 · Answer

Thanks Bunuel. This is very helpful!!

Is x positive? (1) 1/(x+1) < 1/(x-1) where x ≠ 1; x ≠ -1 (2) x is eve

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