That person Boreal gives a lot of WRONG answers.
Let ticketed and vandalized be T and V, respectively
Then P(T or V) = P(T) + P(V) - P(T&V)
My congratulations to the student who will read this @MathTherapy solution, since he (or she) has a beautiful and rare opportunity to learn this basic formula of the Probability theory once and for all from the very vital case/example.