Question
Quantitative Aptitude Question on Properties of Numbers
Any non-zero real numbers x,y such that y=3 and yx<y−3x+3, will satisfy the condition
A
yx<xy
B
If y>10 , then −x>y
C
If x<0 , then −x<y
D
If y<0 , then −x<y
Answer
If y<0 , then −x<y
Explanation
Solution
Given :
yx<y−3x+3, this can be expressed as :
yx−y−3x+3<0
Now,
⇒ y(y−3)x(y−3)−y(x+3)<0
⇒ y(y−3)xy−3x−xy−3y<0
⇒ y(y−3)−3(x+y)<0
⇒ y(y−3)3(x+y)>0
From the above inequality , we can say that :
when y < 0 ⇒ y(y - 3) > 0.
So, to satisfy the above given equation y(y−3)3(x+y)>0,
(x + y) must be greater than zero.
Therefore, x > 0 and |x| > |y|
So, the magnitude of x is greater than the magnitude of y.
Therefore, x > y and |x| > |y| ⇒ -x < y
So, the correct option is (D) : If y<0 , then −x<y.