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Sum of squares of first n natural numbers:

An³
Bn(n+1)(2n+1)/6
Cn(n+1)/2
Dn²(n+1)²/4
Answer & Solution
Correct answer: B. n(n+1)(2n+1)/6
Σk² from 1 to n = n(n+1)(2n+1)/6. For n=10: 10×11×21/6 = 2310/6 = 385. Standard formula. Also Σk³ = [n(n+1)/2]² = (Σk)².
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