Correct Answer: 40
Explanation:
The given series follows the rule, +(11x1), +(11x3), +(11x5), +(11x7), +(11x9),....
So starting from 7, 7 + 11 = 18, 18 + 33 = 51, 51 + 55 = 106, ... So wrong number is 40 which is to be 51.