If -10

Question

If -10 < k < 10, is k > 0 ? (1) 1/k > 0 (2) k^2 > 0

Bunuel · Accepted Answer

If -10 < k < 10, is k > 0 ? (1) 1/k > 0 --> k>0 . Sufficient . (2) k^2 > 0. This statement just says that k eq{0} . Not sufficient. Answer: A. The first statement says that \frac{1}{k} > 0 . Now, if k=0 , then \frac{1}{k}=\frac{1}{0}= undefined (division by zero is not allowed), hence in this case \frac{1}{k}>0 does not hold true, which means that k cannot equal to zero. Hope it's clear. P.S. Please read and follow: rules-for-posting-please-read-this-before-posting-133935.html

heygmat · Answer

u must take the statements are right. u r wrong, if u justify these by evaluation.
in statement 1 says-------1/k is greater than 0 dentes k must be greater than 0 to be valid of this statement.

oh, yes 0 is neither negative nor positive in this connection. your confusion is infinity, does it mean, if k equal to 0, the expression is right.

got it?

appsy01 · Answer

Given -10 < k <10 , is k>0

This is simple if we think the question in terms of sign of k rather than its values

(1) 1/k > 0
1/k is +ve this means k is +ve Sufficient

(2) k^2 > 0
k^2 is +ve means, k could either be +ve or -ve
Insufficient.

Answer is A

LogicGuru1 · Answer

If -10 < k < 10, is k > 0 ? (1) 1/k > 0 It means K cannot be negative because 1 divided by a negative number will yield negative number and by definition -ve<0 so k will always be greater than 0 K>0 yes SUFFICIENT (2) k^2 > 0 Squaring a term takes away its polarity so k can be both negative and positive If k is -ve then 1/-ve will be <0 ; hence the answer will be NO if k is +ve then 1/+ve will be >0 ; hence answer will be YES INSUFFICIENT ANSWER is A

Ben10512 · Answer

Hi experts,
Could you please look into my question. 
As per statement 1) 1/k>0. What I learnt from previous questions is that we cannot decide whether 1/k is positive or negative in such cases. The sign could be negative or positive. Then how can we conclude that k>0. Moreover, it is nowhere mentioned that k is a positive integer.

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Bunuel · Answer

1/k > 0 directly tells us that 1/k is positive (1/k is more than 0). 1/k to be positive k has to be positive. It's that simple. Also, k can be any positive number integer or not.

I think you should brush up basics on inequalities. Check the links below.

9. Inequalities 
     Theory   
 Inequalities Made Easy! 
 Inequalities: Tips and hints 
 Arithmetic with Inequalities 
 Wavy Line Method Application - Complex Algebraic Inequalities 
 Solving Quadratic Inequalities: Graphic Approach 
 Inequalities - Quadratic Inequalities 
 Graphic approach to problems with inequalities 
 Inequalities trick 
 INEQUATIONS(Inequalities) Part 1 
 INEQUATIONS(Inequalities) Part 2 
     Questions   
 Inequality and absolute value questions from my collection 
 DS Questions 
 PS Questions

For more check  Ultimate GMAT Quantitative Megathread

Hope it helps.

hiranmay · Answer

If -10 < k < 10, is k > 0 ? (1) 1/k > 0 --> suff: 1/k > 0 => k/k^2>0 => k > 0 (2) k^2 > 0 --> insuff: k^2 > 0 => k > 0 or k < 0 Answer: A

Kinshook · Answer

Asked: If -10 < k < 10, is k > 0 ? (1) 1/k > 0 k>0 and k<>0 SUFFICIENT (2) k^2 > 0 |k|>0 k eq 0 k may be positive or negative NOT SUFFICIENT IMO A

palaknayyar · Answer

S1: well 1/k > 0 is possible ONLY when k>0. if k<0, this would've been a negative number. Sufficient. Keep A and D, strike off BCE.
S2. square (or for that matter any even powers) will always be positive, no matter the sign of k. Therefore B is not sufficient.

Final answer A. Hope this was helpful.

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If -10 < k < 10, is k > 0 ?

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