Out of five employees, who gets the highest salary? Statement I: 'Z' got the…

In a data-sufficiency question, a statement (or a combination of statements) is sufficient only when it lets you pin down ONE unique answer to the exact question asked. If even the most favourable reading of the given facts still leaves more than one outcome possible, the statement(s) are not sufficient - a plausible-sounding partial link between two of the quantities does not count as sufficiency.

1. Statement I alone: 'Z' has the least salary among the five employees. This fixes only the bottom of the ranking; the remaining four employees, including 'W' and 'X', could be arranged in any order among themselves, so any one of them could be the highest earner. Statement I alone does not identify a single highest earner.

2. Statement II alone: 'W' earns one thousand rupees more than 'X'. This only orders two of the five employees relative to each other; it says nothing about where 'W' or 'X' stand compared to the other three employees. Statement II alone does not identify a single highest earner either.

3. Combining both statements: 'Z' is now known to be the lowest earner, and 'W' is Rs. 1000 ahead of 'X'. But the salaries of the two employees not mentioned in either statement, relative to 'W', are still unknown - one of them could easily earn more than 'W'. So even together, the statements do not fix a single highest earner.

Cross-check: for the statements to be sufficient, every arrangement of salaries consistent with them would have to agree on who earns the most. Here, at least two different arrangements remain possible even after combining both statements - for instance, 'W' could be the highest earner, or an employee not mentioned in either statement could earn even more than 'W'. So no unique highest earner can be determined.

Since neither statement alone, nor both statements together, fix a single highest earner, even both the statements together are not sufficient to answer the question.