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:

6, 12, 21, ?, 48

A 33

B 38

C 40

D 45

ANS:A - 33

Explanation: The pattern is + 6, + 9, + 12, + 15, ..... So, missing term = 21 + 12 = 33.