5, 6, 9, 15, ?, 40

1.	5, 6, 9, 15, ?, 40
Answer» The pattern is + 1, + 3, + 6,....., i.e. + 1, + (1 + 2), + (1 + 2 + 3),..... So, missing term = 15 + (1 + 2 + 3 + 4) = 25.

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