Lessons

General Aptitude
9.1 Numbers - General Questions

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Q.

(22 + 42 + 62 + ... + 202) = ?

View Answer

Correct choice: 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 x 1 x 10 x 11 x 21
6

= (4 x 5 x 77)

= 1540.

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