CA Foundation · Quantitative Aptitude · Sequence and Series
What is the value of the sum of the squares of the first 12 natural numbers, i.e. 1² + 2² + 3² + ... + 12²?
The sum of squares of the first 12 natural numbers is 650. Using the formula n(n+1)(2n+1)/6 with n = 12 gives 12×13×25 divided by 6, which equals 3900/6 = 650.
- A650Correct
- B666
- C78
- D780
Explanation
Sum of squares = n(n+1)(2n+1)/6 = 12×13×25/6 = 3900/6 = 650. The value 78 is the sum of the first 12 natural numbers, not their squares, and 666 is not produced by the formula.
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