Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 80)
80.
(12 + 22 + 32 + ... + 102) = ?
Answer: Option
Explanation:
| We know that (12 + 22 + 32 + ... + n2) = | 1 | n(n + 1)(2n + 1) |
| 6 |
| Putting n = 10, required sum = |  |
1 | x 10 x 11 x 21 |  |
= 385 |
| 6 |
Discussion:
6 comments Page 1 of 1.
Haleem said:
6 years ago
@Prabhat.
2 * 10 + 1 = 21 not 22.
2 * 10 + 1 = 21 not 22.
(1)
Prabhat said:
6 years ago
@Sahana.
n (n+1) (2n+1)/6.
= 10(11) (2*10+1)/6
= 10*11*22/6
= 5*242/3,
= 1210/3,
= 43.33.
n (n+1) (2n+1)/6.
= 10(11) (2*10+1)/6
= 10*11*22/6
= 5*242/3,
= 1210/3,
= 43.33.
Sahana said:
7 years ago
n(n+1)(2n+1)/6 by using this formula we can solve this problem.
(1)
Kovurisainadh said:
8 years ago
Explain it, please.
(1)
Shan said:
10 years ago
How n is taken as 10?
(2)
Sugu said:
1 decade ago
How can get 1/6 here? Any one please explain me?
(3)
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