Find the wrong term in the series given below.9, 18, 34, 54, 79, 109

The series seems to be increasing by a certain pattern. Let's try to find out what that pattern is:

1. The difference between the second term (18) and the first term (9) is 9.
2. The difference between the third term (34) and the second term (18) is 16.
3. The difference between the fourth term (54) and the third term (34) is 20.
4. The difference between the fifth term (79) and the fourth term (54) is 25.
5. The difference between the sixth term (109) and the fifth term (79) is 30.

So, the differences between the terms are increasing by 7, 4, 5, and 5 respectively.

However, if we look at the pattern, it seems like the differences should be increasing by 5 each time (9, 16, 25, etc.). This is a pattern of perfect squares (3^2, 4^2, 5^2, etc.).

Therefore, the third term, 34, is wrong. It should be 18 + 5^2 = 43 to follow the pattern.