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CUET
General Test
Numerical Ability
Number System (1)
Find the average of squares of first five natural numbers.
8
10
11
5
Sum of squares of natural numbers, S = n(n + 1)(2n + 1) / 6 = 5(5+1)(2×5 + 1)/6 = 55
Average = S/5 = 55/5 = 11
The correct answer is Option (3) → 11