In the following question, find the odd letter/number/word pair from the given alternatives.

13 : 40 18 : 55 11 : 34 16 : 51

16 : 51

(13 x 3) + 1 = 40 (18 x 3) + 1 = 55 (11 x 3) + 1 = 34 (16 x 3) + 3 = 51 which is odd