Answer
If it is possible for events $ A\ \text{ and }\ B $ to occur simultaneously, then $ P\left( A\,\text{or }B \right)$ is $ P\left( A \right)+P\left( B \right)-P\left( A\text{ and }B \right)$.
Work Step by Step
We know that if $ A\ \text{ and }\ B $ are not mutually executive events, the probability that either $ A\ \text{or}\ B $ will occur is determined by adding their individual probabilities and also subtracting the probability that $ A\ \text{ and }\ B $ occur simultaneously.
Thus, the probability is:
$ P\left( A\,\text{or }B \right)=P\left( A \right)+P\left( B \right)-P\left( A\text{ and }B \right)$
