saadiagha wrote:is x^y>0

1. Y=2

2. X is an integer

Target question: is x^y > 0

Statement 1: Y=2
There are several pairs of values that meet this condition. Here are two:
Case a: x=1 and y=2, in which case x^y is greater than 0
Case b: x=0 and y=2, in which case x^y is not greater than 0
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: X is an integer
There are several pairs of values that meet this condition. Here are two:
Case a: x=1 and y=2, in which case x^y is greater than 0
Case b: x=0 and y=2, in which case x^y is not greater than 0
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined:
There are several pairs of values that meet both conditions. Here are two:
Case a: x=1 and y=2, in which case x^y is greater than 0
Case b: x=0 and y=2, in which case x^y is not greater than 0
Since we still cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent

saadiagha wrote:Hey Brent, thanks for the solution
will the answer remain the same if the question is reversed, that is;

Is x^y < 0?

1) y = 2.
2) x is an integer.

Let's try it.

Target question: is x^y < 0

Statement 1: Y=2
We know that x^2 > 0 for all values of x.
Given this, we can conclude that x^y is definitely not less than 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: X is an integer
There are several pairs of values that meet this condition. Here are two:
Case a: x= -1 and y=1, in which case x^y is less than 0
Case b: x= 1 and y=1, in which case x^y is not less than 0
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer = A

Cheers,
Brent

saadiagha wrote: P.S- I hope I am posting the question correctly, the sign ^ refers to "raised to the power" right?

Right!

Cheers,
Brent

saadiagha wrote:Let's try it.

Target question: is x^y < 0

Statement 1: Y=2
We know that x^2 > 0 for all values of x.
Given this, we can conclude that x^y is definitely not less than 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT


Ok great! I have one little querry though, I thought we should try values of x between 0 and 1.

In case x=0.5, and y=2, wont the square be 0.25?

How come in our analysis we tried x=1 or -1 but not a non integer?

Its only in the second statement that we realize that x is an integer, and hence can use the info from the first statement- that was my reasoning for choosing C.

Could you tell me where I am messing up here?

Thanks a lot!

I think there might be a mix up between the two different questions we're examining here. The original question asked "Is x^y > 0?" and your follow-up question asked "Is x^y < 0?"

In your question here, you are referring to different parts of different questions. The red part is from my solution to the follow-up question. The green part is referring to my solution to the original question.


If you're asking me why, in the original question, I didn't use non-integer values for x when showing two different cases for statement 1, my answer is that, even though, I was not confined to integer values I still chose to use them. Had I used non-integer values for x, the results would have been the same:

Target question: Is x^y > 0?

Statement 1: Y=2
There are several pairs of values that meet this condition. Here are two:
Case a: x=0.5 and y=2, in which case x^y is greater than 0
Case b: x=0 and y=2, in which case x^y is not greater than 0
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Cheers,
Brent