Hi,
While solving DS inequality questions, the best approach is to always breakdown the question stem if possible. To breakdown the question stem, there are three hygiene factors, that if followed will simplify your analysis of the question.
1. Always keep the RHS of the inequality as 0
2. Simplify the LHS to a product or division of values (product and division of terms are easier to analyze)
3. Always try and maintain even powered terms (as the sign of them will always be 0 or positive)Let us breakdown the question stem here:
Is y - x > 1/(x - y)? Keeping the RHS as 0,
Is (y - x) - 1/(x - y) > 0
Now before we take the LCM, the smarter thing to do will be to obtain a squared term wherever the opportunity arises. Remember a square will always be 0 or positive. Taking -1 common out of the denominator x - y we get,
Is (y - x) + 1/(y - x) > 0
Taking the LCM we get,
Is ((y - x)^2 + 1)/(y - x) > 0.
For this equation to hold, both the numerator and denominator have to be of the same sign. The numerator clearly here is always going to be positive, so the question can be rephrased to
Is y - x > 0?Statement 1 : |x - y| > 1
This implies that x - y > 1 or -(x - y) > 1.
x - y > 1 -----> y - x < -1
-(x - y) > 1 -----> y - x > 1.
So y - x can be positive or negative. Insufficient.
Statement 2 : y > x.
Implies y - x > 0. Sufficient.
Answer : BTakeaway : In Inequality DS questions, always spend time on simplifying the question stem and rephrase the DS question. This will help immensely while working with the two statements and will not require you to plug in values.Hope this helps!
Aditya
CrackVerbal Quant Expert
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