The probability of rain is 0.6, the probability of fog is 0.4, and the probability of rain and fog is 0.15, what is the probability of rain or fog

Probability of rain or fog = 0.85

Step-by-step explanation:

1) Use the formula for non-mutually exclusive events (events that can occur at the same time):

P (rain or fog) = P (rain) + P (fog) - P (rain and fog)

P (rain or fog) = 0.6 + 0.4 - 0.15

P (rain or fog) = 0.85