Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 53)
53.
(112 + 122 + 132 + ... + 202) = ?
Answer: Option
Explanation:
(112 + 122 + 132 + ... + 202) = (12 + 22 + 32 + ... + 202) - (12 + 22 + 32 + ... + 102)
 |
Ref: (12 + 22 + 32 + ... + n2) = | 1 | n(n + 1)(2n + 1) |  |
|
| 6 |
| = |  |
20 x 21 x 41 | - | 10 x 11 x 21 |  |
| 6 | 6 |
= (2870 - 385)
= 2485.
Discussion:
33 comments Page 3 of 4.
Abhimanyu jakhar said:
1 decade ago
Simple method is:
n/2[firstnum + lastnum]-120.
n = 50{totalnum}.
n/2[firstnum + lastnum]-120.
n = 50{totalnum}.
Jitu said:
1 decade ago
i also not got it......
even in formula the no. is divided by 2
even in formula the no. is divided by 2
Tareque said:
9 years ago
10 * 11 * 21 / 6 How it came?
Please explain.
Please explain.
Venkat said:
7 years ago
I can't understand. Please help me to get it.
Beedisha said:
8 years ago
Why we are subtracting 1 to 10 square values?
Anu said:
9 years ago
I can't understand please explain me clearly.
Himansu mohanta said:
7 years ago
What is the value of n here, & how we know?
Sara said:
1 decade ago
I can't understand. Can anyone explain?
Nithish said:
7 years ago
How did ^66 Came? I didn't understand.
Gauri Sharma said:
5 years ago
I didn't got it. Please explain.
(2)
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