Discussion :: Numbers
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(22 + 42 + 62 + ... + 202) = ?
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Answer : Option C
Explanation :
(22 + 42 + 62 + ... + 202) = (1 x 2)2 + (2 x 2)2 + (2 x 3)2 + ... + (2 x 10)2
= (22 x 12) + (22 x 22) + (22 x 32) + ... + (22 x 102)
= 22 x [12 + 22 + 32 + ... + 102]
=\( [4* \frac { 1 } { 6}\)x 10 x 11 x 21]
= (4 x 5 x 77)
= 1540.
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