Answer
P(not born in December) $=\frac{334}{365}\approx0.915$
Work Step by Step
The sample space: a year (365 days). So, N(S) = 365.
The event "a person was not born in December" is the complement of "a person was born in December". December has 31 days, so N(born in December) = 31.
Now:
P(not born in December) = 1 - P(born in December) =
$1-\frac{N(\text{born in December})}{N(S)}=\frac{365}{365}-\frac{31}{365}=\frac{334}{365}\approx0.915$
