Explanation:

The given number series 11, 12.2, 14.6, 18.2, ?

11

11 + 1.2 = 12.2

12.2 + 2.4 = 14.6

14.6 + 3.6 = 18.2

18.2 + 4.8 = 23

Hence, the next number in the given number series is 23.

Hence, option 2 is the correct answer.