A question is given followed by two Statements I and II. Consider the Question and the Statements and mark the correct option.
Mental Ability & Logical Reasoning ·Previously asked in UPSC Civil Services Examination 2025
View the full solved paper: GS Paper II
Question
A question is given followed by two Statements I and II. Consider the Question and the Statements and mark the correct option.
Question: Is (p + q)² − 4pq, where p, q are natural numbers, positive?
Statement I: p < q.
Statement II: p q.
Which one of the following is correct in respect of the above Question and the Statements?
- A. The Question can be answered by using one of the Statements alone, but cannot be answered using the other statement alone.
- B. The Question can be answered by using either Statement alone. (Correct answer)
- C. The Question can be answered by using both the Statements together, but cannot be answered using either Statement alone.
- D. The Question can be answered even without using any of the Statements.
Correct Answer
Option B — The Question can be answered by using either Statement alone.
Detailed Solution & Explanation
The correct answer is The Question can be answered by using either Statement alone..
Key Points
- (p+q)²−4pq = p²+2pq+q²−4pq = p²−2pq+q² = (p−q)².
- This is always ≥ 0. If p ≠ q, it is strictly positive.
- Statement I: p < q → p ≠ q → (p−q)² > 0. Yes, positive.
- Statement II: p > q → p ≠ q → (p−q)² > 0. Yes, positive.
- Either statement alone is sufficient.
- Answer: The Question can be answered by using either Statement alone.