Bunuel
Is \(\frac{x}{yz}>0\)?
(1) \(yz>x^2\)
(2) \(x<y+z\)
Question: \(\frac{x}{yz}>0\)
Inference: For this to be true -
OR
Statement 1(1) \(yz>x^2\)
As \(x^2\) is non-negative, yz is positive in this case.
Hence we can conclude that yz > 0. We however don't know the value of x, hence the statement alone is not sufficient.
Eliminate A and D.
Statement 2(2) \(x<y+z\)
The statement tells us that the value of x is less than the sum of the values of x and y. However, using this information, we cannot predict anything on the sign of x. For example let's take the following two cases -
Case 1:
----- 0 ------------- x ---------- y ------ z -------
In this case, x > 0 and yz > 0 ⇒Is \(\frac{x}{yz}>0\)? -- Yes !
Case 1:
----- x -----(y+z)------- y ---------- x ------ 0 -------
In this case, x < 0 and yz > 0 ⇒Is \(\frac{x}{yz}>0\)? -- No!
As we have two contradicting answers from statement 2, the statement alone is not sufficient. Hence we can eliminate B.
CombinedThe statements combined don't help either as the sign of x can be positive or negative in both of the above statements.
Hence the ambiguity on the sign of x remains when we use both the statements combined.
Option E