Answer:
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