Series Completion - Verbal and Reasoning

Directions to SolveChoose the correct alternative that will continue the same pattern and replace the question mark in the given series.
Q1:

7, 26, 63, 124, 215, 342, ?

A 391

B 421

C 481

D 511

ANS:D - 511

Explanation: The terms of the given series are (23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1),..... So, missing term = (83 - 1) = (512 - 1) = 511.