gmat prep Q, if ab is not equal to zero, and (-b,a)

[shalinibhatia15]

PLS help me solve this DS qUESTION.

If ab is not equal to zero, and points (-a,b) and (-b,a) are in the same quadrant of the xy plane ,is point (-x,y) lie in the same QUADRANT.

1) xy > 0

2) ax > 0

[brijesh.mishra01]

Since ab <> 0 , and points (-a,b) and (-b,a) are in the same quadrant of the xy plane, so we can safely conclude that a and b both are of same sign.

i.e. If both r +ive (a>0, b>0) then points (-a,b) and (-b,a) will lie in 2nd quadrant

If both r -ive (a>0, b>0) then points (-a,b) and (-b,a) will lie in 4th quadrant

Now, come to the main part of the que...i.e. is point (-x,y) lie in the same QUADRANT

1) xy > 0 implies that both x and y are of same sign.Again we can not conlude whether (-x,y) will lie in 2nd or 4th quardant.....INSUFFICIENT

2) ax > 0 implies that both a and x are of same sign, but we do't know anything abt y.Again we can not conlude whether (-x,y) will lie in 2nd or 4th quardant as .....INSUFFICIENT

Using both stmts and given data all the four variables a,b,x,and y will be of same sign.So points (-a,b) ,(-b,a) and (-x,y) will lie in the same quadrant....

Please note that we are not asked to figure out the quadrant in which all are lying.....

[RonPurewal]

try this thread:

if-ab-does-not-equal-zero-t2975.html