Please explain which formula I should use to complete the following probability question: The probability that a family will buy a vacation home in...

Please explain which formula I should use to complete the following probability question:

The probability that a family will buy a vacation home in Miami, malibu, or newport is 0.25, 0.10 and 0.35. What is the probability that the family will choose one of these homes?

What I know:

P(Miami)= 0.25

P(Malibu)=0.10

P(Newport)=0.35

What I want to know:

What formula to use to find the answer