Find the Missing Number in the Following Series:

Answer:  (1) 46

Explanation:-
1, 6, 13, 22, 33, ?

1 + 5 = 6,
6 + (5 + 2)  = 6 + 7 = 13,
13 + (7 + 2) = 13 + 9 = 22,
22  + (9 + 2)  = 22 + 11 = 33,
Similarly,
33 + (11 + 2) = 33 + 13  =  46.

Then,  the missing number is 46.

Hence, the answer is (1) 46.