Consider the Question and two Statements given below:

Question: Is Z brother of X?

Statement-1: X is a brother of Y and Y is a brother of Z.

Statement-2: X, Y and Z are siblings.

Which one of the following is correct in respect of the Question and the Statements?

The correct option is: Both Statement-I and Statement-2 are not sufficient to answer the Question.

To determine if Z is the brother of X, we need to establish two key pieces of information:
1. Z and X are siblings (they share the same parents).
2. Z is male (since a brother must be male).

Let us analyze the given statements step-by-step:

Analysis of Statement-1:
Statement-1 states: "X is a brother of Y and Y is a brother of Z."
- "X is a brother of Y" tells us that X is male and that X and Y are siblings.
- "Y is a brother of Z" tells us that Y is male and that Y and Z are siblings.
- Since X is a sibling of Y, and Y is a sibling of Z, it follows that X, Y, and Z are all siblings.
- However, this statement provides no information about the gender of Z. Z could be male (which would make Z the brother of X) or female (which would make Z the sister of X).
Therefore, Statement-1 alone is not sufficient to answer the question.

Analysis of Statement-2:
Statement-2 states: "X, Y and Z are siblings."
- This statement tells us that X, Y, and Z share the same parents, but it provides no information regarding the gender of Z. Z could be male or female.
Therefore, Statement-2 alone is not sufficient to answer the question.

Combining Statement-1 and Statement-2:
- Even when we combine both statements, we only know that X, Y, and Z are siblings, and that X and Y are males.
- The gender of Z remains unknown. Z can still be either male (brother) or female (sister).
Hence, both Statement-1 and Statement-2 together are not sufficient to answer the Question.