Find the odd one out: 3, 5, 11, 14, 17, 21 MCQ with Answer and Explanation

Explanation:
Pattern: +1, +3, +6, +10, +15 (triangular numbers). 25+16? Differences of differences +2,+3,+4,+5 so next difference +15? 1,3,6,10,15. Yes 25+15=40. Option A.

Explanation:
The series is A, AB, ABC, ABCD, ABCDE, ABCDEF... So after A B C D the next group starts with A B C D E, so next letter is E.

Explanation:
Each term is multiplied by 3 and 1 is subtracted: 2×3-1=5, 5×3-1=14, 14×3-1=41, so 41×3-1=122.