Rahul@gurome wrote:sandysai wrote:Hi Rahul
if ab does not equal 0, and (-a.b) and (-b,a) are in the same quadrant, is (-x,y) in this quadrant?
(1) xy>0
(2) ax>0
Your earlier response:
"Combining (1) and (2), we get to know that x, y and a are all positive or all negative that x, y and a have the same sign"
I have QQ the above statement doesnt give any infernece abour B . To determin ( - x and y) lie in same co-ordinate, wht is there no dependency on "b" . How can we conclude with out considering b variable .?
Please throw some light on this one. Thanks!!
Let's start from the beginning again!
Given: ab does not equal zero, and (-a,b) and (-b,a) are on the same quadrant. These implies,
(i) Neither a nor b is equal to zero (As ab does not equal to zero).
(ii) As (-a,b) and (-b,a) are on the same quadrant. -a and -b should be of same sign. Thus, a and b are of same sign.
These information are available from the question itself.
Statement 1: xy > 0. This implies, x and y are of same sign. Nothing is said about their relation with a or b. So, this is NOT SUFFICIENT to determine whether (-x,y) is in the same quadrant.
Statement 2: ax > 0. This implies, a and x are of same sign. But nothing is mentioned about y. So, this is NOT SUFFICIENT to determine whether (-x,y) is in the same quadrant.
Now if we take both the statements together, we have the following information,
(i) a and b are of same sign. (From the question itself)
(ii) x and y are of same sign. (From Statement 1)
(iii) a and x are of same sign. (From Statement 2)
Combining these information, we get that a, b, x and y are of same sign. Therefore (-a,b), (-b,a) and (-x,y) are in the same quadrant. So, the statements together are sufficient.
The correct answer is C.
Hope this clears the confusions.
