Q: A deck of n numbered cards is thoroughly shuffled and the cards are inserted into n numbered cells one by one. If the card number i falls in the cell i, we count it as a match; otherwise not. What is the variance of total number of such matches?
(a)1
(b)0
(c)1/2
(d)3/4
Correct Answer: (a)
The correct answer is (c): 1/2. Subject: Quantitative Aptitude & Data Interpretation | Sub-topic: Statistics & Probability Note: This answer was determined through AI-based research. Verify against the official answer key when available.