The correct option is D - Select this option if the question cannot be answered even using any of the statements.
[as per provisional answerkey]Analysis
Statement I alone: x2<y<1
This statement tells us that y is greater than x2 and both are less than 1. However, it does not provide a definitive relationship between x and y because x can be positive or negative.
Case 1: Let x=0.1. Then x2=0.01. If y=0.5, then 0.01<0.5<1 is satisfied. Here, y>x.
Case 2: Let x=−0.9. Then x2=0.81. If y=0.85, then 0.81<0.85<1 is satisfied. Here, x<y (since −0.9<0.85).
Case 3: Let x=0.9. Then x2=0.81. If y=0.85, then 0.81<0.85<1 is satisfied. Here, x>y (since 0.9>0.85).
Since we can get both x<y and x>y, Statement I is not sufficient.
Statement II alone: y<x<1
For x to be a real number and less than 1, x must be in the range 0<=x<1. The statement says y < x.
Case 1: Let x=0.25. Then x=0.5. If y=0.1, then 0.1<0.5<1 is satisfied. Here, x>y (0.25>0.1).
Case 2: Let x=0.01. Then x=0.1. If y=0.05, then 0.05<0.1<1 is satisfied. Here, x<y (0.01<0.05).
Since we can get both x<y and x>y, Statement II is not sufficient.
Both statements together:
From Statement II, we know 0<=x<1. In this range, x2<x<x.
Combining the inequalities: x2<y<x<1.
Even with this combined constraint, the relationship between x and y is not fixed. For any x in (0, 1), y is simply trapped between x2 and x. Since x also lies between x2 and x, y could be smaller than x (if it's near x2) or larger than x (if it's near x).
Example: If x=0.25, then x2 = 0.0625 and x=0.5. y can be 0.1 (making x>y) or y can be 0.4 (making x<y). Both values of y satisfy x2<y<x.
Thus, even together, the statements are insufficient.
Why the other options are incorrect
- Option (a) - one statement alone sufficient: As shown above, Statement I fails because x can be negative or positive, and Statement II fails because the relative positions of x and y within the (0, 1) interval are not fixed.
- Option (b) - either statement alone sufficient: This is incorrect because neither statement provides a unique comparison between x and y.
- Option (c) - both statements together sufficient: This is incorrect because even when combined, y is restricted to the interval (x2,x), which contains x itself, allowing y to be either side of x.
Key Concept
In the interval (0, 1), the relative order of powers and roots is x2<x<x; any variable y constrained between the extremes (x2 and x) cannot be definitively compared to the middle value (x) without further information.