JEE Main 2026 Mathematics question
The mean and variance of n observations are 8 and 16, respectively. If the sum of the first (n − 1) observations is 48 and the sum of squares of the first (n − 1) observations is 496, then the value of n is:
Answer: (D)
Solution
The last observation is 8n − 48, and its square is n(16 + 64) − 496 = 80n − 496. Setting
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